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How to Write a Lab Report – with Example/Template
April 11, 2024
Perhaps you’re in the midst of your challenging AP chemistry class in high school, or perhaps college you’re enrolled in biology , chemistry , or physics at university. At some point, you will likely be asked to write a lab report. Sometimes, your teacher or professor will give you specific instructions for how to format and write your lab report, and if so, use that. In case you’re left to your own devices, here are some guidelines you might find useful. Continue reading for the main elements of a lab report, followed by a detailed description of the more writing-heavy parts (with a lab report example/lab report template). Lastly, we’ve included an outline that can help get you started.
What is a lab report?
A lab report is an overview of your experiment. Essentially, it explains what you did in the experiment and how it went. Most lab reports end up being 5-10 pages long (graphs or other images included), though the length depends on the experiment. Here are some brief explanations of the essential parts of a lab report:
Title : The title says, in the most straightforward way possible, what you did in the experiment. Often, the title looks something like, “Effects of ____ on _____.” Sometimes, a lab report also requires a title page, which includes your name (and the names of any lab partners), your instructor’s name, and the date of the experiment.
Abstract : This is a short description of key findings of the experiment so that a potential reader could get an idea of the experiment before even beginning.
Introduction : This is comprised of one or several paragraphs summarizing the purpose of the lab. The introduction usually includes the hypothesis, as well as some background information.
Lab Report Example (Continued)
Materials : Perhaps the simplest part of your lab report, this is where you list everything needed for the completion of your experiment.
Methods : This is where you describe your experimental procedure. The section provides necessary information for someone who would want to replicate your study. In paragraph form, write out your methods in chronological order, though avoid excessive detail.
Data : Here, you should document what happened in the experiment, step-by-step. This section often includes graphs and tables with data, as well as descriptions of patterns and trends. You do not need to interpret all of the data in this section, but you can describe trends or patterns, and state which findings are interesting and/or significant.
Discussion of results : This is the overview of your findings from the experiment, with an explanation of how they pertain to your hypothesis, as well as any anomalies or errors.
Conclusion : Your conclusion will sum up the results of your experiment, as well as their significance. Sometimes, conclusions also suggest future studies.
Sources : Often in APA style , you should list all texts that helped you with your experiment. Make sure to include course readings, outside sources, and other experiments that you may have used to design your own.
How to write the abstract
The abstract is the experiment stated “in a nutshell”: the procedure, results, and a few key words. The purpose of the academic abstract is to help a potential reader get an idea of the experiment so they can decide whether to read the full paper. So, make sure your abstract is as clear and direct as possible, and under 200 words (though word count varies).
When writing an abstract for a scientific lab report, we recommend covering the following points:
- Background : Why was this experiment conducted?
- Objectives : What problem is being addressed by this experiment?
- Methods : How was the study designed and conducted?
- Results : What results were found and what do they mean?
- Conclusion : Were the results expected? Is this problem better understood now than before? If so, how?
How to write the introduction
The introduction is another summary, of sorts, so it could be easy to confuse the introduction with the abstract. While the abstract tends to be around 200 words summarizing the entire study, the introduction can be longer if necessary, covering background information on the study, what you aim to accomplish, and your hypothesis. Unlike the abstract (or the conclusion), the introduction does not need to state the results of the experiment.
Here is a possible order with which you can organize your lab report introduction:
- Intro of the intro : Plainly state what your study is doing.
- Background : Provide a brief overview of the topic being studied. This could include key terms and definitions. This should not be an extensive literature review, but rather, a window into the most relevant topics a reader would need to understand in order to understand your research.
- Importance : Now, what are the gaps in existing research? Given the background you just provided, what questions do you still have that led you to conduct this experiment? Are you clarifying conflicting results? Are you undertaking a new area of research altogether?
- Prediction: The plants placed by the window will grow faster than plants placed in the dark corner.
- Hypothesis: Basil plants placed in direct sunlight for 2 hours per day grow at a higher rate than basil plants placed in direct sunlight for 30 minutes per day.
- How you test your hypothesis : This is an opportunity to briefly state how you go about your experiment, but this is not the time to get into specific details about your methods (save this for your results section). Keep this part down to one sentence, and voila! You have your introduction.
How to write a discussion section
Here, we’re skipping ahead to the next writing-heavy section, which will directly follow the numeric data of your experiment. The discussion includes any calculations and interpretations based on this data. In other words, it says, “Now that we have the data, why should we care?” This section asks, how does this data sit in relation to the hypothesis? Does it prove your hypothesis or disprove it? The discussion is also a good place to mention any mistakes that were made during the experiment, and ways you would improve the experiment if you were to repeat it. Like the other written sections, it should be as concise as possible.
Here is a list of points to cover in your lab report discussion:
- Weaker statement: These findings prove that basil plants grow more quickly in the sunlight.
- Stronger statement: These findings support the hypothesis that basil plants placed in direct sunlight grow at a higher rate than basil plants given less direct sunlight.
- Factors influencing results : This is also an opportunity to mention any anomalies, errors, or inconsistencies in your data. Perhaps when you tested the first round of basil plants, the days were sunnier than the others. Perhaps one of the basil pots broke mid-experiment so it needed to be replanted, which affected your results. If you were to repeat the study, how would you change it so that the results were more consistent?
- Implications : How do your results contribute to existing research? Here, refer back to the gaps in research that you mentioned in your introduction. Do these results fill these gaps as you hoped?
- Questions for future research : Based on this, how might your results contribute to future research? What are the next steps, or the next experiments on this topic? Make sure this does not become too broad—keep it to the scope of this project.
How to write a lab report conclusion
This is your opportunity to briefly remind the reader of your findings and finish strong. Your conclusion should be especially concise (avoid going into detail on findings or introducing new information).
Here are elements to include as you write your conclusion, in about 1-2 sentences each:
- Restate your goals : What was the main question of your experiment? Refer back to your introduction—similar language is okay.
- Restate your methods : In a sentence or so, how did you go about your experiment?
- Key findings : Briefly summarize your main results, but avoid going into detail.
- Limitations : What about your experiment was less-than-ideal, and how could you improve upon the experiment in future studies?
- Significance and future research : Why is your research important? What are the logical next-steps for studying this topic?
Template for beginning your lab report
Here is a compiled outline from the bullet points in these sections above, with some examples based on the (overly-simplistic) basil growth experiment. Hopefully this will be useful as you begin your lab report.
1) Title (ex: Effects of Sunlight on Basil Plant Growth )
2) Abstract (approx. 200 words)
- Background ( This experiment looks at… )
- Objectives ( It aims to contribute to research on…)
- Methods ( It does so through a process of…. )
- Results (Findings supported the hypothesis that… )
- Conclusion (These results contribute to a wider understanding about…)
3) Introduction (approx. 1-2 paragraphs)
- Intro ( This experiment looks at… )
- Background ( Past studies on basil plant growth and sunlight have found…)
- Importance ( This experiment will contribute to these past studies by…)
- Hypothesis ( Basil plants placed in direct sunlight for 2 hours per day grow at a higher rate than basil plants placed in direct sunlight for 30 minutes per day.)
- How you will test your hypothesis ( This hypothesis will be tested by a process of…)
4) Materials (list form) (ex: pots, soil, seeds, tables/stands, water, light source )
5) Methods (approx. 1-2 paragraphs) (ex: 10 basil plants were measured throughout a span of…)
6) Data (brief description and figures) (ex: These charts demonstrate a pattern that the basil plants placed in direct sunlight…)
7) Discussion (approx. 2-3 paragraphs)
- Support or reject hypothesis ( These findings support the hypothesis that basil plants placed in direct sunlight grow at a higher rate than basil plants given less direct sunlight.)
- Factors that influenced your results ( Outside factors that could have altered the results include…)
- Implications ( These results contribute to current research on basil plant growth and sunlight because…)
- Questions for further research ( Next steps for this research could include…)
- Restate your goals ( In summary, the goal of this experiment was to measure…)
- Restate your methods ( This hypothesis was tested by…)
- Key findings ( The findings supported the hypothesis because…)
- Limitations ( Although, certain elements were overlooked, including…)
- Significance and future research ( This experiment presents possibilities of future research contributions, such as…)
- Sources (approx. 1 page, usually in APA style)
Final thoughts – Lab Report Example
Hopefully, these descriptions have helped as you write your next lab report. Remember that different instructors may have different preferences for structure and format, so make sure to double-check when you receive your assignment. All in all, make sure to keep your scientific lab report concise, focused, honest, and organized. Good luck!
For more reading on coursework success, check out the following articles:
- How to Write the AP Lang Argument Essay (With Example)
- How to Write the AP Lang Rhetorical Analysis Essay (With Example)
- 49 Most Interesting Biology Research Topics
- 50 Best Environmental Science Research Topics
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Writing the Experimental Report: Overview, Introductions, and Literature Reviews
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Experimental reports (also known as "lab reports") are reports of empirical research conducted by their authors. You should think of an experimental report as a "story" of your research in which you lead your readers through your experiment. As you are telling this story, you are crafting an argument about both the validity and reliability of your research, what your results mean, and how they fit into other previous work.
These next two sections provide an overview of the experimental report in APA format. Always check with your instructor, advisor, or journal editor for specific formatting guidelines.
General-specific-general format
Experimental reports follow a general to specific to general pattern. Your report will start off broadly in your introduction and discussion of the literature; the report narrows as it leads up to your specific hypotheses, methods, and results. Your discussion transitions from talking about your specific results to more general ramifications, future work, and trends relating to your research.
Experimental reports in APA format have a title page. Title page formatting is as follows:
- A running head and page number in the upper right corner (right aligned)
- A definition of running head in IN ALL CAPS below the running head (left aligned)
- Vertically and horizontally centered paper title, followed by author and affiliation
Please see our sample APA title page .
Crafting your story
Before you begin to write, carefully consider your purpose in writing: what is it that you discovered, would like to share, or would like to argue? You can see report writing as crafting a story about your research and your findings. Consider the following.
- What is the story you would like to tell?
- What literature best speaks to that story?
- How do your results tell the story?
- How can you discuss the story in broad terms?
During each section of your paper, you should be focusing on your story. Consider how each sentence, each paragraph, and each section contributes to your overall purpose in writing. Here is a description of one student's process.
Briel is writing an experimental report on her results from her experimental psychology lab class. She was interested in looking at the role gender plays in persuading individuals to take financial risks. After her data analysis, she finds that men are more easily persuaded by women to take financial risks and that men are generally willing to take more financial risks.
When Briel begins to write, she focuses her introduction on financial risk taking and gender, focusing on male behaviors. She then presents relevant literature on financial risk taking and gender that help illuminate her own study, but also help demonstrate the need for her own work. Her introduction ends with a study overview that directly leads from the literature review. Because she has already broadly introduced her study through her introduction and literature review, her readers can anticipate where she is going when she gets to her study overview. Her methods and results continue that story. Finally, her discussion concludes that story, discussing her findings, implications of her work, and the need for more research in the area of gender and financial risk taking.
The abstract gives a concise summary of the contents of the report.
- Abstracts should be brief (about 100 words)
- Abstracts should be self-contained and provide a complete picture of what the study is about
- Abstracts should be organized just like your experimental report—introduction, literature review, methods, results and discussion
- Abstracts should be written last during your drafting stage
Introduction
The introduction in an experimental article should follow a general to specific pattern, where you first introduce the problem generally and then provide a short overview of your own study. The introduction includes three parts: opening statements, literature review, and study overview.
Opening statements: Define the problem broadly in plain English and then lead into the literature review (this is the "general" part of the introduction). Your opening statements should already be setting the stage for the story you are going to tell.
Literature review: Discusses literature (previous studies) relevant to your current study in a concise manner. Keep your story in mind as you organize your lit review and as you choose what literature to include. The following are tips when writing your literature review.
- You should discuss studies that are directly related to your problem at hand and that logically lead to your own hypotheses.
- You do not need to provide a complete historical overview nor provide literature that is peripheral to your own study.
- Studies should be presented based on themes or concepts relevant to your research, not in a chronological format.
- You should also consider what gap in the literature your own research fills. What hasn't been examined? What does your work do that others have not?
Study overview: The literature review should lead directly into the last section of the introduction—your study overview. Your short overview should provide your hypotheses and briefly describe your method. The study overview functions as a transition to your methods section.
You should always give good, descriptive names to your hypotheses that you use consistently throughout your study. When you number hypotheses, readers must go back to your introduction to find them, which makes your piece more difficult to read. Using descriptive names reminds readers what your hypotheses were and allows for better overall flow.
In our example above, Briel had three different hypotheses based on previous literature. Her first hypothesis, the "masculine risk-taking hypothesis" was that men would be more willing to take financial risks overall. She clearly named her hypothesis in the study overview, and then referred back to it in her results and discussion sections.
Thais and Sanford (2000) recommend the following organization for introductions.
- Provide an introduction to your topic
- Provide a very concise overview of the literature
- State your hypotheses and how they connect to the literature
- Provide an overview of the methods for investigation used in your research
Bem (2006) provides the following rules of thumb for writing introductions.
- Write in plain English
- Take the time and space to introduce readers to your problem step-by-step; do not plunge them into the middle of the problem without an introduction
- Use examples to illustrate difficult or unfamiliar theories or concepts. The more complicated the concept or theory, the more important it is to have clear examples
- Open with a discussion about people and their behavior, not about psychologists and their research
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Step-by-Step Guide: How to Craft a Strong Research Hypothesis
- 4 minute read
- 386.6K views
Table of Contents
A research hypothesis is a concise statement about the expected result of an experiment or project. In many ways, a research hypothesis represents the starting point for a scientific endeavor, as it establishes a tentative assumption that is eventually substantiated or falsified, ultimately improving our certainty about the subject investigated.
To help you with this and ease the process, in this article, we discuss the purpose of research hypotheses and list the most essential qualities of a compelling hypothesis. Let’s find out!
How to Craft a Research Hypothesis
Crafting a research hypothesis begins with a comprehensive literature review to identify a knowledge gap in your field. Once you find a question or problem, come up with a possible answer or explanation, which becomes your hypothesis. Now think about the specific methods of experimentation that can prove or disprove the hypothesis, which ultimately lead to the results of the study.
Enlisted below are some standard formats in which you can formulate a hypothesis¹ :
- A hypothesis can use the if/then format when it seeks to explore the correlation between two variables in a study primarily.
Example: If administered drug X, then patients will experience reduced fatigue from cancer treatment.
- A hypothesis can adopt when X/then Y format when it primarily aims to expose a connection between two variables
Example: When workers spend a significant portion of their waking hours in sedentary work , then they experience a greater frequency of digestive problems.
- A hypothesis can also take the form of a direct statement.
Example: Drug X and drug Y reduce the risk of cognitive decline through the same chemical pathways
What are the Features of an Effective Hypothesis?
Hypotheses in research need to satisfy specific criteria to be considered scientifically rigorous. Here are the most notable qualities of a strong hypothesis:
- Testability: Ensure the hypothesis allows you to work towards observable and testable results.
- Brevity and objectivity: Present your hypothesis as a brief statement and avoid wordiness.
- Clarity and Relevance: The hypothesis should reflect a clear idea of what we know and what we expect to find out about a phenomenon and address the significant knowledge gap relevant to a field of study.
Understanding Null and Alternative Hypotheses in Research
There are two types of hypotheses used commonly in research that aid statistical analyses. These are known as the null hypothesis and the alternative hypothesis . A null hypothesis is a statement assumed to be factual in the initial phase of the study.
For example, if a researcher is testing the efficacy of a new drug, then the null hypothesis will posit that the drug has no benefits compared to an inactive control or placebo . Suppose the data collected through a drug trial leads a researcher to reject the null hypothesis. In that case, it is considered to substantiate the alternative hypothesis in the above example, that the new drug provides benefits compared to the placebo.
Let’s take a closer look at the null hypothesis and alternative hypothesis with two more examples:
Null Hypothesis:
The rate of decline in the number of species in habitat X in the last year is the same as in the last 100 years when controlled for all factors except the recent wildfires.
In the next experiment, the researcher will experimentally reject this null hypothesis in order to confirm the following alternative hypothesis :
The rate of decline in the number of species in habitat X in the last year is different from the rate of decline in the last 100 years when controlled for all factors other than the recent wildfires.
In the pair of null and alternative hypotheses stated above, a statistical comparison of the rate of species decline over a century and the preceding year will help the research experimentally test the null hypothesis, helping to draw scientifically valid conclusions about two factors—wildfires and species decline.
We also recommend that researchers pay attention to contextual echoes and connections when writing research hypotheses. Research hypotheses are often closely linked to the introduction ² , such as the context of the study, and can similarly influence the reader’s judgment of the relevance and validity of the research hypothesis.
Seasoned experts, such as professionals at Elsevier Language Services, guide authors on how to best embed a hypothesis within an article so that it communicates relevance and credibility. Contact us if you want help in ensuring readers find your hypothesis robust and unbiased.
References
- Hypotheses – The University Writing Center. (n.d.). https://writingcenter.tamu.edu/writing-speaking-guides/hypotheses
- Shaping the research question and hypothesis. (n.d.). Students. https://students.unimelb.edu.au/academic-skills/graduate-research-services/writing-thesis-sections-part-2/shaping-the-research-question-and-hypothesis
Systematic Literature Review or Literature Review?
How to Write an Effective Problem Statement for Your Research Paper
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- How to Write a Strong Hypothesis | Guide & Examples
How to Write a Strong Hypothesis | Guide & Examples
Published on 6 May 2022 by Shona McCombes .
A hypothesis is a statement that can be tested by scientific research. If you want to test a relationship between two or more variables, you need to write hypotheses before you start your experiment or data collection.
Table of contents
What is a hypothesis, developing a hypothesis (with example), hypothesis examples, frequently asked questions about writing hypotheses.
A hypothesis states your predictions about what your research will find. It is a tentative answer to your research question that has not yet been tested. For some research projects, you might have to write several hypotheses that address different aspects of your research question.
A hypothesis is not just a guess – it should be based on existing theories and knowledge. It also has to be testable, which means you can support or refute it through scientific research methods (such as experiments, observations, and statistical analysis of data).
Variables in hypotheses
Hypotheses propose a relationship between two or more variables . An independent variable is something the researcher changes or controls. A dependent variable is something the researcher observes and measures.
In this example, the independent variable is exposure to the sun – the assumed cause . The dependent variable is the level of happiness – the assumed effect .
Prevent plagiarism, run a free check.
Step 1: ask a question.
Writing a hypothesis begins with a research question that you want to answer. The question should be focused, specific, and researchable within the constraints of your project.
Step 2: Do some preliminary research
Your initial answer to the question should be based on what is already known about the topic. Look for theories and previous studies to help you form educated assumptions about what your research will find.
At this stage, you might construct a conceptual framework to identify which variables you will study and what you think the relationships are between them. Sometimes, you’ll have to operationalise more complex constructs.
Step 3: Formulate your hypothesis
Now you should have some idea of what you expect to find. Write your initial answer to the question in a clear, concise sentence.
Step 4: Refine your hypothesis
You need to make sure your hypothesis is specific and testable. There are various ways of phrasing a hypothesis, but all the terms you use should have clear definitions, and the hypothesis should contain:
- The relevant variables
- The specific group being studied
- The predicted outcome of the experiment or analysis
Step 5: Phrase your hypothesis in three ways
To identify the variables, you can write a simple prediction in if … then form. The first part of the sentence states the independent variable and the second part states the dependent variable.
In academic research, hypotheses are more commonly phrased in terms of correlations or effects, where you directly state the predicted relationship between variables.
If you are comparing two groups, the hypothesis can state what difference you expect to find between them.
Step 6. Write a null hypothesis
If your research involves statistical hypothesis testing , you will also have to write a null hypothesis. The null hypothesis is the default position that there is no association between the variables. The null hypothesis is written as H 0 , while the alternative hypothesis is H 1 or H a .
Research question | Hypothesis | Null hypothesis |
---|---|---|
What are the health benefits of eating an apple a day? | Increasing apple consumption in over-60s will result in decreasing frequency of doctor’s visits. | Increasing apple consumption in over-60s will have no effect on frequency of doctor’s visits. |
Which airlines have the most delays? | Low-cost airlines are more likely to have delays than premium airlines. | Low-cost and premium airlines are equally likely to have delays. |
Can flexible work arrangements improve job satisfaction? | Employees who have flexible working hours will report greater job satisfaction than employees who work fixed hours. | There is no relationship between working hour flexibility and job satisfaction. |
How effective is secondary school sex education at reducing teen pregnancies? | Teenagers who received sex education lessons throughout secondary school will have lower rates of unplanned pregnancy than teenagers who did not receive any sex education. | Secondary school sex education has no effect on teen pregnancy rates. |
What effect does daily use of social media have on the attention span of under-16s? | There is a negative correlation between time spent on social media and attention span in under-16s. | There is no relationship between social media use and attention span in under-16s. |
Hypothesis testing is a formal procedure for investigating our ideas about the world using statistics. It is used by scientists to test specific predictions, called hypotheses , by calculating how likely it is that a pattern or relationship between variables could have arisen by chance.
A hypothesis is not just a guess. It should be based on existing theories and knowledge. It also has to be testable, which means you can support or refute it through scientific research methods (such as experiments, observations, and statistical analysis of data).
A research hypothesis is your proposed answer to your research question. The research hypothesis usually includes an explanation (‘ x affects y because …’).
A statistical hypothesis, on the other hand, is a mathematical statement about a population parameter. Statistical hypotheses always come in pairs: the null and alternative hypotheses. In a well-designed study , the statistical hypotheses correspond logically to the research hypothesis.
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How the Experimental Method Works in Psychology
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The Experimental Process
Types of experiments, potential pitfalls of the experimental method.
The experimental method is a type of research procedure that involves manipulating variables to determine if there is a cause-and-effect relationship. The results obtained through the experimental method are useful but do not prove with 100% certainty that a singular cause always creates a specific effect. Instead, they show the probability that a cause will or will not lead to a particular effect.
At a Glance
While there are many different research techniques available, the experimental method allows researchers to look at cause-and-effect relationships. Using the experimental method, researchers randomly assign participants to a control or experimental group and manipulate levels of an independent variable. If changes in the independent variable lead to changes in the dependent variable, it indicates there is likely a causal relationship between them.
What Is the Experimental Method in Psychology?
The experimental method involves manipulating one variable to determine if this causes changes in another variable. This method relies on controlled research methods and random assignment of study subjects to test a hypothesis.
For example, researchers may want to learn how different visual patterns may impact our perception. Or they might wonder whether certain actions can improve memory . Experiments are conducted on many behavioral topics, including:
The scientific method forms the basis of the experimental method. This is a process used to determine the relationship between two variables—in this case, to explain human behavior .
Positivism is also important in the experimental method. It refers to factual knowledge that is obtained through observation, which is considered to be trustworthy.
When using the experimental method, researchers first identify and define key variables. Then they formulate a hypothesis, manipulate the variables, and collect data on the results. Unrelated or irrelevant variables are carefully controlled to minimize the potential impact on the experiment outcome.
History of the Experimental Method
The idea of using experiments to better understand human psychology began toward the end of the nineteenth century. Wilhelm Wundt established the first formal laboratory in 1879.
Wundt is often called the father of experimental psychology. He believed that experiments could help explain how psychology works, and used this approach to study consciousness .
Wundt coined the term "physiological psychology." This is a hybrid of physiology and psychology, or how the body affects the brain.
Other early contributors to the development and evolution of experimental psychology as we know it today include:
- Gustav Fechner (1801-1887), who helped develop procedures for measuring sensations according to the size of the stimulus
- Hermann von Helmholtz (1821-1894), who analyzed philosophical assumptions through research in an attempt to arrive at scientific conclusions
- Franz Brentano (1838-1917), who called for a combination of first-person and third-person research methods when studying psychology
- Georg Elias Müller (1850-1934), who performed an early experiment on attitude which involved the sensory discrimination of weights and revealed how anticipation can affect this discrimination
Key Terms to Know
To understand how the experimental method works, it is important to know some key terms.
Dependent Variable
The dependent variable is the effect that the experimenter is measuring. If a researcher was investigating how sleep influences test scores, for example, the test scores would be the dependent variable.
Independent Variable
The independent variable is the variable that the experimenter manipulates. In the previous example, the amount of sleep an individual gets would be the independent variable.
A hypothesis is a tentative statement or a guess about the possible relationship between two or more variables. In looking at how sleep influences test scores, the researcher might hypothesize that people who get more sleep will perform better on a math test the following day. The purpose of the experiment, then, is to either support or reject this hypothesis.
Operational definitions are necessary when performing an experiment. When we say that something is an independent or dependent variable, we must have a very clear and specific definition of the meaning and scope of that variable.
Extraneous Variables
Extraneous variables are other variables that may also affect the outcome of an experiment. Types of extraneous variables include participant variables, situational variables, demand characteristics, and experimenter effects. In some cases, researchers can take steps to control for extraneous variables.
Demand Characteristics
Demand characteristics are subtle hints that indicate what an experimenter is hoping to find in a psychology experiment. This can sometimes cause participants to alter their behavior, which can affect the results of the experiment.
Intervening Variables
Intervening variables are factors that can affect the relationship between two other variables.
Confounding Variables
Confounding variables are variables that can affect the dependent variable, but that experimenters cannot control for. Confounding variables can make it difficult to determine if the effect was due to changes in the independent variable or if the confounding variable may have played a role.
Psychologists, like other scientists, use the scientific method when conducting an experiment. The scientific method is a set of procedures and principles that guide how scientists develop research questions, collect data, and come to conclusions.
The five basic steps of the experimental process are:
- Identifying a problem to study
- Devising the research protocol
- Conducting the experiment
- Analyzing the data collected
- Sharing the findings (usually in writing or via presentation)
Most psychology students are expected to use the experimental method at some point in their academic careers. Learning how to conduct an experiment is important to understanding how psychologists prove and disprove theories in this field.
There are a few different types of experiments that researchers might use when studying psychology. Each has pros and cons depending on the participants being studied, the hypothesis, and the resources available to conduct the research.
Lab Experiments
Lab experiments are common in psychology because they allow experimenters more control over the variables. These experiments can also be easier for other researchers to replicate. The drawback of this research type is that what takes place in a lab is not always what takes place in the real world.
Field Experiments
Sometimes researchers opt to conduct their experiments in the field. For example, a social psychologist interested in researching prosocial behavior might have a person pretend to faint and observe how long it takes onlookers to respond.
This type of experiment can be a great way to see behavioral responses in realistic settings. But it is more difficult for researchers to control the many variables existing in these settings that could potentially influence the experiment's results.
Quasi-Experiments
While lab experiments are known as true experiments, researchers can also utilize a quasi-experiment. Quasi-experiments are often referred to as natural experiments because the researchers do not have true control over the independent variable.
A researcher looking at personality differences and birth order, for example, is not able to manipulate the independent variable in the situation (personality traits). Participants also cannot be randomly assigned because they naturally fall into pre-existing groups based on their birth order.
So why would a researcher use a quasi-experiment? This is a good choice in situations where scientists are interested in studying phenomena in natural, real-world settings. It's also beneficial if there are limits on research funds or time.
Field experiments can be either quasi-experiments or true experiments.
Examples of the Experimental Method in Use
The experimental method can provide insight into human thoughts and behaviors, Researchers use experiments to study many aspects of psychology.
A 2019 study investigated whether splitting attention between electronic devices and classroom lectures had an effect on college students' learning abilities. It found that dividing attention between these two mediums did not affect lecture comprehension. However, it did impact long-term retention of the lecture information, which affected students' exam performance.
An experiment used participants' eye movements and electroencephalogram (EEG) data to better understand cognitive processing differences between experts and novices. It found that experts had higher power in their theta brain waves than novices, suggesting that they also had a higher cognitive load.
A study looked at whether chatting online with a computer via a chatbot changed the positive effects of emotional disclosure often received when talking with an actual human. It found that the effects were the same in both cases.
One experimental study evaluated whether exercise timing impacts information recall. It found that engaging in exercise prior to performing a memory task helped improve participants' short-term memory abilities.
Sometimes researchers use the experimental method to get a bigger-picture view of psychological behaviors and impacts. For example, one 2018 study examined several lab experiments to learn more about the impact of various environmental factors on building occupant perceptions.
A 2020 study set out to determine the role that sensation-seeking plays in political violence. This research found that sensation-seeking individuals have a higher propensity for engaging in political violence. It also found that providing access to a more peaceful, yet still exciting political group helps reduce this effect.
While the experimental method can be a valuable tool for learning more about psychology and its impacts, it also comes with a few pitfalls.
Experiments may produce artificial results, which are difficult to apply to real-world situations. Similarly, researcher bias can impact the data collected. Results may not be able to be reproduced, meaning the results have low reliability .
Since humans are unpredictable and their behavior can be subjective, it can be hard to measure responses in an experiment. In addition, political pressure may alter the results. The subjects may not be a good representation of the population, or groups used may not be comparable.
And finally, since researchers are human too, results may be degraded due to human error.
What This Means For You
Every psychological research method has its pros and cons. The experimental method can help establish cause and effect, and it's also beneficial when research funds are limited or time is of the essence.
At the same time, it's essential to be aware of this method's pitfalls, such as how biases can affect the results or the potential for low reliability. Keeping these in mind can help you review and assess research studies more accurately, giving you a better idea of whether the results can be trusted or have limitations.
Colorado State University. Experimental and quasi-experimental research .
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Mayrhofer R, Kuhbandner C, Lindner C. The practice of experimental psychology: An inevitably postmodern endeavor . Front Psychol . 2021;11:612805. doi:10.3389/fpsyg.2020.612805
Mandler G. A History of Modern Experimental Psychology .
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Meyer A, Hackert B, Weger U. Franz Brentano and the beginning of experimental psychology: implications for the study of psychological phenomena today . Psychol Res . 2018;82:245-254. doi:10.1007/s00426-016-0825-7
Britannica. Georg Elias Müller .
McCambridge J, de Bruin M, Witton J. The effects of demand characteristics on research participant behaviours in non-laboratory settings: A systematic review . PLoS ONE . 2012;7(6):e39116. doi:10.1371/journal.pone.0039116
Laboratory experiments . In: The Sage Encyclopedia of Communication Research Methods. Allen M, ed. SAGE Publications, Inc. doi:10.4135/9781483381411.n287
Schweizer M, Braun B, Milstone A. Research methods in healthcare epidemiology and antimicrobial stewardship — quasi-experimental designs . Infect Control Hosp Epidemiol . 2016;37(10):1135-1140. doi:10.1017/ice.2016.117
Glass A, Kang M. Dividing attention in the classroom reduces exam performance . Educ Psychol . 2019;39(3):395-408. doi:10.1080/01443410.2018.1489046
Keskin M, Ooms K, Dogru AO, De Maeyer P. Exploring the cognitive load of expert and novice map users using EEG and eye tracking . ISPRS Int J Geo-Inf . 2020;9(7):429. doi:10.3390.ijgi9070429
Ho A, Hancock J, Miner A. Psychological, relational, and emotional effects of self-disclosure after conversations with a chatbot . J Commun . 2018;68(4):712-733. doi:10.1093/joc/jqy026
Haynes IV J, Frith E, Sng E, Loprinzi P. Experimental effects of acute exercise on episodic memory function: Considerations for the timing of exercise . Psychol Rep . 2018;122(5):1744-1754. doi:10.1177/0033294118786688
Torresin S, Pernigotto G, Cappelletti F, Gasparella A. Combined effects of environmental factors on human perception and objective performance: A review of experimental laboratory works . Indoor Air . 2018;28(4):525-538. doi:10.1111/ina.12457
Schumpe BM, Belanger JJ, Moyano M, Nisa CF. The role of sensation seeking in political violence: An extension of the significance quest theory . J Personal Social Psychol . 2020;118(4):743-761. doi:10.1037/pspp0000223
By Kendra Cherry, MSEd Kendra Cherry, MS, is a psychosocial rehabilitation specialist, psychology educator, and author of the "Everything Psychology Book."
Princeton Correspondents on Undergraduate Research
How to Write An Effective Lab Report
Whether you are in lab for general chemistry, independent work, or senior thesis, almost all lab experiments will be followed up with a lab report or paper. Although it should be relatively easy to write about an experiment you completed, this is often the most difficult part of lab work, especially when the results are unexpected. In this post, I will outline the components of a lab report while offering tips on how to write one.
Understand Your Experiments Thoroughly
Before you begin writing your draft, it is important that you understand your experiment, as this will help you decide what to include in your paper. When I wrote my first organic chemistry lab report, I rushed to begin answering the discussion questions only to realize halfway through that I had a major conceptual error. Because of this, I had to revise most of what I had written so far, which cost me a lot of time. Know what the purpose of the lab is, formulate the hypothesis, and begin to think about the results you are expecting. At this point, it is helpful to check in with your Lab TA, mentor, or principal investigator (PI) to ensure that you thoroughly understand your project.
The abstract of your lab report will generally consist of a short summary of your entire report, typically in the same order as your report. Although this is the first section of your lab report, this should be the last section you write. Rather than trying to follow your entire report based on your abstract, it is easier if you write your report first before trying to summarize it.
Introduction and Background
The introduction and background of your report should establish the purpose of your experiment (what principles you are examining), your hypothesis (what you expect to see and why), and relevant findings from others in the field. You have likely done extensive reading about the project from textbooks, lecture notes, or scholarly articles. But as you write, only include background information that is relevant to your specific experiments. For instance, over the summer when I was still learning about metabolic engineering and its role in yeast cells, I read several articles detailing this process. However, a lot of this information was a very broad introduction to the field and not directly related to my project, so I decided not to include most of it.
This section of the lab report should not contain a step-by-step procedure of your experiments, but rather enough details should be included so that someone else can understand and replicate what you did. From this section, the reader should understand how you tested your hypothesis and why you chose that method. Explain the different parts of your project, the variables being tested, and controls in your experiments. This section will validate the data presented by confirming that variables are being tested in a proper way.
You cannot change the data you collect from your experiments; thus the results section will be written for you. Your job is to present these results in appropriate tables and charts. Depending on the length of your project, you may have months of data from experiments or just a three-hour lab period worth of results. For example, for in-class lab reports, there is usually only one major experiment, so I include most of the data I collect in my lab report. But for longer projects such as summer internships, there are various preliminary experiments throughout, so I select the data to include. Although you cannot change the data, you must choose what is relevant to include in your report. Determine what is included in your report based on the goals and purpose of your project.
Discussion and Conclusion
In this section, you should analyze your results and relate your data back to your hypothesis. You should mention whether the results you obtained matched what was expected and the conclusions that can be drawn from this. For this section, you should talk about your data and conclusions with your lab mentors or TAs before you begin writing. As I mentioned above, by consulting with your mentors, you will avoid making large conceptual error that may take a long time to address.
There is no correct order for how to write a report, but it is generally easier to write some sections before others. For instance, because your results cannot be changed, it is easier to write the results section first. Likewise, because you also cannot change the methods you used in your experiment, it is helpful to write this section after writing your results. Although there are multiple ways to write and format a lab report or research paper, the goals of every report are the same: to describe what you did, your results, and why they are significant. As you write, keep your audience and these goals in mind.
— Saira Reyes, Engineering Correspondent
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Writing Studio
Writing a lab report: introduction and discussion section guide.
In an effort to make our handouts more accessible, we have begun converting our PDF handouts to web pages. Download this page as a PDF: Writing a Lab Report Return to Writing Studio Handouts
Part 1 (of 2): Introducing a Lab Report
The introduction of a lab report states the objective of the experiment and provides the reader with background information. State the topic of your report clearly and concisely (in one or two sentences). Provide background theory, previous research, or formulas the reader should know. Usually, an instructor does not want you to repeat whatever the lab manual says, but to show your understanding of the problem.
Questions an Effective Lab Report Introduction Should Answer
What is the problem.
Describe the problem investigated. Summarize relevant research to provide context, key terms, and concepts so that your reader can understand the experiment.
Why is it important?
Review relevant research to provide a rationale for the investigation. What conflict, unanswered question, untested population, or untried method in existing research does your experiment address? How will you challenge or extend the findings of other researchers?
What solution (or step toward a solution) do you propose?
Briefly describe your experiment : hypothesis , research question , general experimental design or method , and a justification of your method (if alternatives exist).
Tips on Composing Your Lab Report’s Introduction
- Move from the general to the specific – from a problem in research literature to the specifics of your experiment.
- Engage your reader – answer the questions: “What did I do?” “Why should my reader care?”
- Clarify the links between problem and solution, between question asked and research design, and between prior research and the specifics of your experiment.
- Be selective, not exhaustive, in choosing studies to cite and the amount of detail to include. In general, the more relevant an article is to your study, the more space it deserves and the later in the introduction it appears.
- Ask your instructor whether or not you should summarize results and/or conclusions in the Introduction.
- “The objective of the experiment was …”
- “The purpose of this report is …”
- “Bragg’s Law for diffraction is …”
- “The scanning electron microscope produces micrographs …”
Part 2 (of 2): Writing the “Discussion” Section of a Lab Report
The discussion is the most important part of your lab report, because here you show that you have not merely completed the experiment, but that you also understand its wider implications. The discussion section is reserved for putting experimental results in the context of the larger theory. Ask yourself: “What is the significance or meaning of the results?”
Elements of an Effective Discussion Section
What do the results indicate clearly? Based on your results, explain what you know with certainty and draw conclusions.
Interpretation
What is the significance of your results? What ambiguities exist? What are logical explanations for problems in the data? What questions might you raise about the methods used or the validity of the experiment? What can be logically deduced from your analysis?
Tips on the Discussion Section
1. explain your results in terms of theoretical issues..
How well has the theory been illustrated? What are the theoretical implications and practical applications of your results?
For each major result:
- Describe the patterns, principles, and relationships that your results show.
- Explain how your results relate to expectations and to literature cited in your Introduction. Explain any agreements, contradictions, or exceptions.
- Describe what additional research might resolve contradictions or explain exceptions.
2. Relate results to your experimental objective(s).
If you set out to identify an unknown metal by finding its lattice parameter and its atomic structure, be sure that you have identified the metal and its attributes.
3. Compare expected results with those obtained.
If there were differences, how can you account for them? Were the instruments able to measure precisely? Was the sample contaminated? Did calculated values take account of friction?
4. Analyze experimental error along with the strengths and limitations of the experiment’s design.
Were any errors avoidable? Were they the result of equipment? If the flaws resulted from the experiment design, explain how the design might be improved. Consider, as well, the precision of the instruments that were used.
5. Compare your results to similar investigations.
In some cases, it is legitimate to compare outcomes with classmates, not in order to change your answer, but in order to look for and to account for or analyze any anomalies between the groups. Also, consider comparing your results to published scientific literature on the topic.
The “Introducing a Lab Report” guide was adapted from the University of Toronto Engineering Communications Centre and University of Wisconsin-Madison Writing Center.
The “Writing the Discussion Section of a Lab Report” resource was adapted from the University of Toronto Engineering Communications Centre and University of Wisconsin-Madison Writing Center.
Last revised: 07/2008 | Adapted for web delivery: 02/2021
In order to access certain content on this page, you may need to download Adobe Acrobat Reader or an equivalent PDF viewer software.
What Is a Hypothesis? (Science)
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A hypothesis (plural hypotheses) is a proposed explanation for an observation. The definition depends on the subject.
In science, a hypothesis is part of the scientific method. It is a prediction or explanation that is tested by an experiment. Observations and experiments may disprove a scientific hypothesis, but can never entirely prove one.
In the study of logic, a hypothesis is an if-then proposition, typically written in the form, "If X , then Y ."
In common usage, a hypothesis is simply a proposed explanation or prediction, which may or may not be tested.
Writing a Hypothesis
Most scientific hypotheses are proposed in the if-then format because it's easy to design an experiment to see whether or not a cause and effect relationship exists between the independent variable and the dependent variable . The hypothesis is written as a prediction of the outcome of the experiment.
Null Hypothesis and Alternative Hypothesis
Statistically, it's easier to show there is no relationship between two variables than to support their connection. So, scientists often propose the null hypothesis . The null hypothesis assumes changing the independent variable will have no effect on the dependent variable.
In contrast, the alternative hypothesis suggests changing the independent variable will have an effect on the dependent variable. Designing an experiment to test this hypothesis can be trickier because there are many ways to state an alternative hypothesis.
For example, consider a possible relationship between getting a good night's sleep and getting good grades. The null hypothesis might be stated: "The number of hours of sleep students get is unrelated to their grades" or "There is no correlation between hours of sleep and grades."
An experiment to test this hypothesis might involve collecting data, recording average hours of sleep for each student and grades. If a student who gets eight hours of sleep generally does better than students who get four hours of sleep or 10 hours of sleep, the hypothesis might be rejected.
But the alternative hypothesis is harder to propose and test. The most general statement would be: "The amount of sleep students get affects their grades." The hypothesis might also be stated as "If you get more sleep, your grades will improve" or "Students who get nine hours of sleep have better grades than those who get more or less sleep."
In an experiment, you can collect the same data, but the statistical analysis is less likely to give you a high confidence limit.
Usually, a scientist starts out with the null hypothesis. From there, it may be possible to propose and test an alternative hypothesis, to narrow down the relationship between the variables.
Example of a Hypothesis
Examples of a hypothesis include:
- If you drop a rock and a feather, (then) they will fall at the same rate.
- Plants need sunlight in order to live. (if sunlight, then life)
- Eating sugar gives you energy. (if sugar, then energy)
- White, Jay D. Research in Public Administration . Conn., 1998.
- Schick, Theodore, and Lewis Vaughn. How to Think about Weird Things: Critical Thinking for a New Age . McGraw-Hill Higher Education, 2002.
- Scientific Method Flow Chart
- Six Steps of the Scientific Method
- What Are the Elements of a Good Hypothesis?
- What Are Examples of a Hypothesis?
- What Is a Testable Hypothesis?
- Null Hypothesis Examples
- Scientific Hypothesis Examples
- Scientific Variable
- Scientific Method Vocabulary Terms
- Understanding Simple vs Controlled Experiments
- What Is a Controlled Experiment?
- What Is an Experimental Constant?
- What Is the Difference Between a Control Variable and Control Group?
- DRY MIX Experiment Variables Acronym
- Random Error vs. Systematic Error
- The Role of a Controlled Variable in an Experiment
How to Develop a Good Research Hypothesis
The story of a research study begins by asking a question. Researchers all around the globe are asking curious questions and formulating research hypothesis. However, whether the research study provides an effective conclusion depends on how well one develops a good research hypothesis. Research hypothesis examples could help researchers get an idea as to how to write a good research hypothesis.
This blog will help you understand what is a research hypothesis, its characteristics and, how to formulate a research hypothesis
Table of Contents
What is Hypothesis?
Hypothesis is an assumption or an idea proposed for the sake of argument so that it can be tested. It is a precise, testable statement of what the researchers predict will be outcome of the study. Hypothesis usually involves proposing a relationship between two variables: the independent variable (what the researchers change) and the dependent variable (what the research measures).
What is a Research Hypothesis?
Research hypothesis is a statement that introduces a research question and proposes an expected result. It is an integral part of the scientific method that forms the basis of scientific experiments. Therefore, you need to be careful and thorough when building your research hypothesis. A minor flaw in the construction of your hypothesis could have an adverse effect on your experiment. In research, there is a convention that the hypothesis is written in two forms, the null hypothesis, and the alternative hypothesis (called the experimental hypothesis when the method of investigation is an experiment).
Characteristics of a Good Research Hypothesis
As the hypothesis is specific, there is a testable prediction about what you expect to happen in a study. You may consider drawing hypothesis from previously published research based on the theory.
A good research hypothesis involves more effort than just a guess. In particular, your hypothesis may begin with a question that could be further explored through background research.
To help you formulate a promising research hypothesis, you should ask yourself the following questions:
- Is the language clear and focused?
- What is the relationship between your hypothesis and your research topic?
- Is your hypothesis testable? If yes, then how?
- What are the possible explanations that you might want to explore?
- Does your hypothesis include both an independent and dependent variable?
- Can you manipulate your variables without hampering the ethical standards?
- Does your research predict the relationship and outcome?
- Is your research simple and concise (avoids wordiness)?
- Is it clear with no ambiguity or assumptions about the readers’ knowledge
- Is your research observable and testable results?
- Is it relevant and specific to the research question or problem?
The questions listed above can be used as a checklist to make sure your hypothesis is based on a solid foundation. Furthermore, it can help you identify weaknesses in your hypothesis and revise it if necessary.
Source: Educational Hub
How to formulate a research hypothesis.
A testable hypothesis is not a simple statement. It is rather an intricate statement that needs to offer a clear introduction to a scientific experiment, its intentions, and the possible outcomes. However, there are some important things to consider when building a compelling hypothesis.
1. State the problem that you are trying to solve.
Make sure that the hypothesis clearly defines the topic and the focus of the experiment.
2. Try to write the hypothesis as an if-then statement.
Follow this template: If a specific action is taken, then a certain outcome is expected.
3. Define the variables
Independent variables are the ones that are manipulated, controlled, or changed. Independent variables are isolated from other factors of the study.
Dependent variables , as the name suggests are dependent on other factors of the study. They are influenced by the change in independent variable.
4. Scrutinize the hypothesis
Evaluate assumptions, predictions, and evidence rigorously to refine your understanding.
Types of Research Hypothesis
The types of research hypothesis are stated below:
1. Simple Hypothesis
It predicts the relationship between a single dependent variable and a single independent variable.
2. Complex Hypothesis
It predicts the relationship between two or more independent and dependent variables.
3. Directional Hypothesis
It specifies the expected direction to be followed to determine the relationship between variables and is derived from theory. Furthermore, it implies the researcher’s intellectual commitment to a particular outcome.
4. Non-directional Hypothesis
It does not predict the exact direction or nature of the relationship between the two variables. The non-directional hypothesis is used when there is no theory involved or when findings contradict previous research.
5. Associative and Causal Hypothesis
The associative hypothesis defines interdependency between variables. A change in one variable results in the change of the other variable. On the other hand, the causal hypothesis proposes an effect on the dependent due to manipulation of the independent variable.
6. Null Hypothesis
Null hypothesis states a negative statement to support the researcher’s findings that there is no relationship between two variables. There will be no changes in the dependent variable due the manipulation of the independent variable. Furthermore, it states results are due to chance and are not significant in terms of supporting the idea being investigated.
7. Alternative Hypothesis
It states that there is a relationship between the two variables of the study and that the results are significant to the research topic. An experimental hypothesis predicts what changes will take place in the dependent variable when the independent variable is manipulated. Also, it states that the results are not due to chance and that they are significant in terms of supporting the theory being investigated.
Research Hypothesis Examples of Independent and Dependent Variables
Research Hypothesis Example 1 The greater number of coal plants in a region (independent variable) increases water pollution (dependent variable). If you change the independent variable (building more coal factories), it will change the dependent variable (amount of water pollution).
Research Hypothesis Example 2 What is the effect of diet or regular soda (independent variable) on blood sugar levels (dependent variable)? If you change the independent variable (the type of soda you consume), it will change the dependent variable (blood sugar levels)
You should not ignore the importance of the above steps. The validity of your experiment and its results rely on a robust testable hypothesis. Developing a strong testable hypothesis has few advantages, it compels us to think intensely and specifically about the outcomes of a study. Consequently, it enables us to understand the implication of the question and the different variables involved in the study. Furthermore, it helps us to make precise predictions based on prior research. Hence, forming a hypothesis would be of great value to the research. Here are some good examples of testable hypotheses.
More importantly, you need to build a robust testable research hypothesis for your scientific experiments. A testable hypothesis is a hypothesis that can be proved or disproved as a result of experimentation.
Importance of a Testable Hypothesis
To devise and perform an experiment using scientific method, you need to make sure that your hypothesis is testable. To be considered testable, some essential criteria must be met:
- There must be a possibility to prove that the hypothesis is true.
- There must be a possibility to prove that the hypothesis is false.
- The results of the hypothesis must be reproducible.
Without these criteria, the hypothesis and the results will be vague. As a result, the experiment will not prove or disprove anything significant.
What are your experiences with building hypotheses for scientific experiments? What challenges did you face? How did you overcome these challenges? Please share your thoughts with us in the comments section.
Frequently Asked Questions
The steps to write a research hypothesis are: 1. Stating the problem: Ensure that the hypothesis defines the research problem 2. Writing a hypothesis as an 'if-then' statement: Include the action and the expected outcome of your study by following a ‘if-then’ structure. 3. Defining the variables: Define the variables as Dependent or Independent based on their dependency to other factors. 4. Scrutinizing the hypothesis: Identify the type of your hypothesis
Hypothesis testing is a statistical tool which is used to make inferences about a population data to draw conclusions for a particular hypothesis.
Hypothesis in statistics is a formal statement about the nature of a population within a structured framework of a statistical model. It is used to test an existing hypothesis by studying a population.
Research hypothesis is a statement that introduces a research question and proposes an expected result. It forms the basis of scientific experiments.
The different types of hypothesis in research are: • Null hypothesis: Null hypothesis is a negative statement to support the researcher’s findings that there is no relationship between two variables. • Alternate hypothesis: Alternate hypothesis predicts the relationship between the two variables of the study. • Directional hypothesis: Directional hypothesis specifies the expected direction to be followed to determine the relationship between variables. • Non-directional hypothesis: Non-directional hypothesis does not predict the exact direction or nature of the relationship between the two variables. • Simple hypothesis: Simple hypothesis predicts the relationship between a single dependent variable and a single independent variable. • Complex hypothesis: Complex hypothesis predicts the relationship between two or more independent and dependent variables. • Associative and casual hypothesis: Associative and casual hypothesis predicts the relationship between two or more independent and dependent variables. • Empirical hypothesis: Empirical hypothesis can be tested via experiments and observation. • Statistical hypothesis: A statistical hypothesis utilizes statistical models to draw conclusions about broader populations.
Wow! You really simplified your explanation that even dummies would find it easy to comprehend. Thank you so much.
Thanks a lot for your valuable guidance.
I enjoy reading the post. Hypotheses are actually an intrinsic part in a study. It bridges the research question and the methodology of the study.
Useful piece!
This is awesome.Wow.
It very interesting to read the topic, can you guide me any specific example of hypothesis process establish throw the Demand and supply of the specific product in market
Nicely explained
It is really a useful for me Kindly give some examples of hypothesis
It was a well explained content ,can you please give me an example with the null and alternative hypothesis illustrated
clear and concise. thanks.
So Good so Amazing
Good to learn
Thanks a lot for explaining to my level of understanding
Explained well and in simple terms. Quick read! Thank you
It awesome. It has really positioned me in my research project
Brief and easily digested
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Experiment Definition in Science – What Is a Science Experiment?
In science, an experiment is simply a test of a hypothesis in the scientific method . It is a controlled examination of cause and effect. Here is a look at what a science experiment is (and is not), the key factors in an experiment, examples, and types of experiments.
Experiment Definition in Science
By definition, an experiment is a procedure that tests a hypothesis. A hypothesis, in turn, is a prediction of cause and effect or the predicted outcome of changing one factor of a situation. Both the hypothesis and experiment are components of the scientific method. The steps of the scientific method are:
- Make observations.
- Ask a question or identify a problem.
- State a hypothesis.
- Perform an experiment that tests the hypothesis.
- Based on the results of the experiment, either accept or reject the hypothesis.
- Draw conclusions and report the outcome of the experiment.
Key Parts of an Experiment
The two key parts of an experiment are the independent and dependent variables. The independent variable is the one factor that you control or change in an experiment. The dependent variable is the factor that you measure that responds to the independent variable. An experiment often includes other types of variables , but at its heart, it’s all about the relationship between the independent and dependent variable.
Examples of Experiments
Fertilizer and plant size.
For example, you think a certain fertilizer helps plants grow better. You’ve watched your plants grow and they seem to do better when they have the fertilizer compared to when they don’t. But, observations are only the beginning of science. So, you state a hypothesis: Adding fertilizer increases plant size. Note, you could have stated the hypothesis in different ways. Maybe you think the fertilizer increases plant mass or fruit production, for example. However you state the hypothesis, it includes both the independent and dependent variables. In this case, the independent variable is the presence or absence of fertilizer. The dependent variable is the response to the independent variable, which is the size of the plants.
Now that you have a hypothesis, the next step is designing an experiment that tests it. Experimental design is very important because the way you conduct an experiment influences its outcome. For example, if you use too small of an amount of fertilizer you may see no effect from the treatment. Or, if you dump an entire container of fertilizer on a plant you could kill it! So, recording the steps of the experiment help you judge the outcome of the experiment and aid others who come after you and examine your work. Other factors that might influence your results might include the species of plant and duration of the treatment. Record any conditions that might affect the outcome. Ideally, you want the only difference between your two groups of plants to be whether or not they receive fertilizer. Then, measure the height of the plants and see if there is a difference between the two groups.
Salt and Cookies
You don’t need a lab for an experiment. For example, consider a baking experiment. Let’s say you like the flavor of salt in your cookies, but you’re pretty sure the batch you made using extra salt fell a bit flat. If you double the amount of salt in a recipe, will it affect their size? Here, the independent variable is the amount of salt in the recipe and the dependent variable is cookie size.
Test this hypothesis with an experiment. Bake cookies using the normal recipe (your control group ) and bake some using twice the salt (the experimental group). Make sure it’s the exact same recipe. Bake the cookies at the same temperature and for the same time. Only change the amount of salt in the recipe. Then measure the height or diameter of the cookies and decide whether to accept or reject the hypothesis.
Examples of Things That Are Not Experiments
Based on the examples of experiments, you should see what is not an experiment:
- Making observations does not constitute an experiment. Initial observations often lead to an experiment, but are not a substitute for one.
- Making a model is not an experiment.
- Neither is making a poster.
- Just trying something to see what happens is not an experiment. You need a hypothesis or prediction about the outcome.
- Changing a lot of things at once isn’t an experiment. You only have one independent and one dependent variable. However, in an experiment, you might suspect the independent variable has an effect on a separate. So, you design a new experiment to test this.
Types of Experiments
There are three main types of experiments: controlled experiments, natural experiments, and field experiments,
- Controlled experiment : A controlled experiment compares two groups of samples that differ only in independent variable. For example, a drug trial compares the effect of a group taking a placebo (control group) against those getting the drug (the treatment group). Experiments in a lab or home generally are controlled experiments
- Natural experiment : Another name for a natural experiment is a quasi-experiment. In this type of experiment, the researcher does not directly control the independent variable, plus there may be other variables at play. Here, the goal is establishing a correlation between the independent and dependent variable. For example, in the formation of new elements a scientist hypothesizes that a certain collision between particles creates a new atom. But, other outcomes may be possible. Or, perhaps only decay products are observed that indicate the element, and not the new atom itself. Many fields of science rely on natural experiments, since controlled experiments aren’t always possible.
- Field experiment : While a controlled experiments takes place in a lab or other controlled setting, a field experiment occurs in a natural setting. Some phenomena cannot be readily studied in a lab or else the setting exerts an influence that affects the results. So, a field experiment may have higher validity. However, since the setting is not controlled, it is also subject to external factors and potential contamination. For example, if you study whether a certain plumage color affects bird mate selection, a field experiment in a natural environment eliminates the stressors of an artificial environment. Yet, other factors that could be controlled in a lab may influence results. For example, nutrition and health are controlled in a lab, but not in the field.
- Bailey, R.A. (2008). Design of Comparative Experiments . Cambridge: Cambridge University Press. ISBN 9780521683579.
- di Francia, G. Toraldo (1981). The Investigation of the Physical World . Cambridge University Press. ISBN 0-521-29925-X.
- Hinkelmann, Klaus; Kempthorne, Oscar (2008). Design and Analysis of Experiments. Volume I: Introduction to Experimental Design (2nd ed.). Wiley. ISBN 978-0-471-72756-9.
- Holland, Paul W. (December 1986). “Statistics and Causal Inference”. Journal of the American Statistical Association . 81 (396): 945–960. doi: 10.2307/2289064
- Stohr-Hunt, Patricia (1996). “An Analysis of Frequency of Hands-on Experience and Science Achievement”. Journal of Research in Science Teaching . 33 (1): 101–109. doi: 10.1002/(SICI)1098-2736(199601)33:1<101::AID-TEA6>3.0.CO;2-Z
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Hypothesis Testing | A Step-by-Step Guide with Easy Examples
Published on November 8, 2019 by Rebecca Bevans . Revised on June 22, 2023.
Hypothesis testing is a formal procedure for investigating our ideas about the world using statistics . It is most often used by scientists to test specific predictions, called hypotheses, that arise from theories.
There are 5 main steps in hypothesis testing:
- State your research hypothesis as a null hypothesis and alternate hypothesis (H o ) and (H a or H 1 ).
- Collect data in a way designed to test the hypothesis.
- Perform an appropriate statistical test .
- Decide whether to reject or fail to reject your null hypothesis.
- Present the findings in your results and discussion section.
Though the specific details might vary, the procedure you will use when testing a hypothesis will always follow some version of these steps.
Table of contents
Step 1: state your null and alternate hypothesis, step 2: collect data, step 3: perform a statistical test, step 4: decide whether to reject or fail to reject your null hypothesis, step 5: present your findings, other interesting articles, frequently asked questions about hypothesis testing.
After developing your initial research hypothesis (the prediction that you want to investigate), it is important to restate it as a null (H o ) and alternate (H a ) hypothesis so that you can test it mathematically.
The alternate hypothesis is usually your initial hypothesis that predicts a relationship between variables. The null hypothesis is a prediction of no relationship between the variables you are interested in.
- H 0 : Men are, on average, not taller than women. H a : Men are, on average, taller than women.
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For a statistical test to be valid , it is important to perform sampling and collect data in a way that is designed to test your hypothesis. If your data are not representative, then you cannot make statistical inferences about the population you are interested in.
There are a variety of statistical tests available, but they are all based on the comparison of within-group variance (how spread out the data is within a category) versus between-group variance (how different the categories are from one another).
If the between-group variance is large enough that there is little or no overlap between groups, then your statistical test will reflect that by showing a low p -value . This means it is unlikely that the differences between these groups came about by chance.
Alternatively, if there is high within-group variance and low between-group variance, then your statistical test will reflect that with a high p -value. This means it is likely that any difference you measure between groups is due to chance.
Your choice of statistical test will be based on the type of variables and the level of measurement of your collected data .
- an estimate of the difference in average height between the two groups.
- a p -value showing how likely you are to see this difference if the null hypothesis of no difference is true.
Based on the outcome of your statistical test, you will have to decide whether to reject or fail to reject your null hypothesis.
In most cases you will use the p -value generated by your statistical test to guide your decision. And in most cases, your predetermined level of significance for rejecting the null hypothesis will be 0.05 – that is, when there is a less than 5% chance that you would see these results if the null hypothesis were true.
In some cases, researchers choose a more conservative level of significance, such as 0.01 (1%). This minimizes the risk of incorrectly rejecting the null hypothesis ( Type I error ).
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The results of hypothesis testing will be presented in the results and discussion sections of your research paper , dissertation or thesis .
In the results section you should give a brief summary of the data and a summary of the results of your statistical test (for example, the estimated difference between group means and associated p -value). In the discussion , you can discuss whether your initial hypothesis was supported by your results or not.
In the formal language of hypothesis testing, we talk about rejecting or failing to reject the null hypothesis. You will probably be asked to do this in your statistics assignments.
However, when presenting research results in academic papers we rarely talk this way. Instead, we go back to our alternate hypothesis (in this case, the hypothesis that men are on average taller than women) and state whether the result of our test did or did not support the alternate hypothesis.
If your null hypothesis was rejected, this result is interpreted as “supported the alternate hypothesis.”
These are superficial differences; you can see that they mean the same thing.
You might notice that we don’t say that we reject or fail to reject the alternate hypothesis . This is because hypothesis testing is not designed to prove or disprove anything. It is only designed to test whether a pattern we measure could have arisen spuriously, or by chance.
If we reject the null hypothesis based on our research (i.e., we find that it is unlikely that the pattern arose by chance), then we can say our test lends support to our hypothesis . But if the pattern does not pass our decision rule, meaning that it could have arisen by chance, then we say the test is inconsistent with our hypothesis .
If you want to know more about statistics , methodology , or research bias , make sure to check out some of our other articles with explanations and examples.
- Normal distribution
- Descriptive statistics
- Measures of central tendency
- Correlation coefficient
Methodology
- Cluster sampling
- Stratified sampling
- Types of interviews
- Cohort study
- Thematic analysis
Research bias
- Implicit bias
- Cognitive bias
- Survivorship bias
- Availability heuristic
- Nonresponse bias
- Regression to the mean
Hypothesis testing is a formal procedure for investigating our ideas about the world using statistics. It is used by scientists to test specific predictions, called hypotheses , by calculating how likely it is that a pattern or relationship between variables could have arisen by chance.
A hypothesis states your predictions about what your research will find. It is a tentative answer to your research question that has not yet been tested. For some research projects, you might have to write several hypotheses that address different aspects of your research question.
A hypothesis is not just a guess — it should be based on existing theories and knowledge. It also has to be testable, which means you can support or refute it through scientific research methods (such as experiments, observations and statistical analysis of data).
Null and alternative hypotheses are used in statistical hypothesis testing . The null hypothesis of a test always predicts no effect or no relationship between variables, while the alternative hypothesis states your research prediction of an effect or relationship.
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Loftus and Palmer (1974): Car Crash Experiment
Saul McLeod, PhD
Editor-in-Chief for Simply Psychology
BSc (Hons) Psychology, MRes, PhD, University of Manchester
Saul McLeod, PhD., is a qualified psychology teacher with over 18 years of experience in further and higher education. He has been published in peer-reviewed journals, including the Journal of Clinical Psychology.
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Psychologist Elizabeth Loftus has been particularly concerned with how subsequent information can affect an eyewitness’s account of an event.
Her main focus has been on the influence of (mis)leading information regarding both visual imagery and wording of questions concerning eyewitness testimony.
A leading question is a question that suggests what answer is desired or leads to the desired answer.
Loftus’ findings indicate that memory for an event that has been witnessed is highly flexible. If someone is exposed to new information during the interval between witnessing the event and recalling it, this new information may have marked effects on what they recall. The original memory can be modified, changed or supplemented.
The fact that eyewitness testimony can be unreliable and influenced by leading questions is illustrated by the classic psychology study by Loftus and Palmer (1974), Reconstruction of Automobile Destruction, described below.
To test their hypothesis that the language used in eyewitness testimony can alter memory.
Thus, they aimed to show that leading questions could distort eyewitness testimony accounts and so have a confabulating effect, as the account would become distorted by cues provided in the question.
To test this, Loftus and Palmer (1974) asked people to estimate the speed of motor vehicles using different forms of questions.
Estimating vehicle speed is something people are generally poor at, so they may be more open to suggestions.
Experiment One: 5 verbs in leading questions
Forty-five American students from the University of Washington formed an opportunity sample.
This was a laboratory experiment with five conditions, only one of which was experienced by each participant (an independent measures experimental design ).
Seven films of traffic accidents, ranging in duration from 5 to 30 seconds, were presented to each group in random order.
After watching the film, participants were asked to describe what had happened as if they were eyewitnesses.
They were then asked specific questions, including the question “About how fast were the cars going when they (smashed / collided / bumped / hit / contacted) each other?”
Thus, the IV was the verb of the question, and the DV was the speed reported by the participants.
The estimated speed was affected by the verb used. The verb implied information about the speed, which systematically affected the participants’ memory of the accident.
Participants who were asked the “smashed” question thought the cars were going faster than those who were asked the “hit” question.
The participants in the “smashed” condition reported the highest speed estimate (40.8 mph), followed by “collided” (39.3 mph), “bumped” (38.1 mph), “hit” (34 mph), and “contacted” (31.8 mph) in descending order.
The results show that the verb conveyed an impression of the speed the car was traveling and this altered the participants” perceptions.
In other words, eyewitness testimony might be biased by the way questions are asked after a crime is committed.
Loftus and Palmer offer two possible explanations for this result:
- Response-bias factors : The misleading information provided may have influenced the answer a person gave (a “response-bias”), but didn’t actually lead to a false memory of the event. For example, the different speed estimates occur because the critical word (e.g., “smash” or “hit”) influences or biases a person’s response.
- The memory representation is altered : The critical verb changes a person’s perception of the accident—some critical words would lead someone to perceive the accident as more serious. This perception is then stored in a person’s memory of the event.
If the second explanation is true, we expect participants to remember other details that are not. Loftus and Palmer tested this in their second experiment.
Experiment Two: The broken glass manipulation
A second experiment was conducted with the aim of investigating is leading questions simply create a response bias, or if they actually alter a person’s memory representation.
150 students were shown a one-minute film which featured a car driving through the countryside followed by four seconds of a multiple traffic accident.
Afterward, the students were questioned about the film. The independent variable was the type of question asked.
- 50 participants were asked “how fast were the car going when they hit each other?”,
- 50 participants were asked, “How fast were the cars going when they smashed each other?”
- the remaining 50 participants were not asked a question about the car’s speed (i.e., the control group).
One week later, the dependent variable was measured – without seeing the film again, they answered ten questions, one of which was a critical one randomly placed in the list:
“Did you see any broken glass? Yes or no?”
There was no broken glass in the original film.
Participants were asked how fast the cars were going when they smashed were more likely to report seeing broken glass.
This research suggests that questioning techniques easily distorts memory, and information acquired after an event can merge with original memory, causing inaccurate recall or reconstructive memory.
The results from experiment two suggest that this effect is not just due to a response bias because leading questions altered the participant’s memory for the event.
The addition of false details to a memory of an event is referred to as confabulation. This has important implications for the questions used in police interviews of eyewitnesses .
Consequently, Loftus and Palmer support the reconstructive memory hypothesis – arguing that information gathered at the time of an event is modified by data gathered afterward.
Over time, information from these two sources is integrated so that it is impossible to separate them—in effect, we have only one memory.
High level of control
Perhaps the greatest strength of Loftus and Palmer’s experiment is the degree of control over confounding variables . As the study was lab-based, the researchers could ensure that a range of factors (age of participants, incident viewed, environment, etc).
Consequently, they could ensure that these factors did not affect the respondents’ answers and that only the verb condition was causing the participants to reevaluate their memories.
Practical Implications
The reconstructive memory hypothesis is extremely useful as a psychological explanation, for instance, in formulating guidelines for police questioning witnesses and suspects.
The conclusion that leading questions can affect memory has important implications for interviewing witnesses , both by police immediately or soon after an event and also by lawyers in court sometime later.
Interviewers should avoid leading questions and be careful to word questions in a way that does not suggest an answer to the person they are interviewing.
The study also had real-world implications; based on evidence such as Loftus’s, the Devlin Report (1976) recommended that trial judges instruct juries that it is not safe to convict on a single eyewitness testimony alone.
A strength of the study is it’s easy to replicate (i.e. copy). This is because the method was a laboratory experiment which followed a standardized procedure.
Low ecological validity
One limitation of the research is that it lacked mundane realism / ecological validity. Participants viewed video clips rather than being present at a real-life accident.
As the video clip does not have the same emotional impact as witnessing a real-life accident, the participants would be less likely to pay attention and less motivated to be accurate in their judgments.
Furthermore, watching a real crash provides much more context—the participants were cued to watch the video, whereas crashes in real life are largely unexpected.
In an experiment, you may expect to be asked questions about what you are watching, which may make you attend the film differently.
In real life, the answers you give may have consequences, which may put pressure on the witness.
Overall, we can probably conclude that this laboratory experiment had low ecological validity and thus may not tell us very much about how people’s memories are affected by leading questions in real life.
Conflicting research
A study conducted by Yuille and Cutshall (1986) conflicts with the findings of this study. They found that misleading information did not alter the memory of people who had witnessed a real armed robbery.
This implies that misleading information may have a greater influence in the lab rather and that Loftus and Palmer’s study may have lacked ecological validity.
He was especially interested in the characteristics of people whom he considered to have achieved their potential as individuals.
Biased Sample
A further problem with the study was the use of students as participants. Students are not representative of the general population in several ways.
Differences between students and the broader population, such as age, memory abilities, learning habits, driving experience, and susceptibility to demand characteristics, could make it difficult to generalize the findings.
Importantly, they may be less experienced drivers and, therefore, less confident in their ability to estimate speeds. This may have influenced them to be more swayed by the verb in the question.
Demand Characteristics
Participants know they are in a laboratory experiment, which will affect their behavior in several ways. They will be looking for clues on how to behave (demand characteristics), and they will usually want to help the experimenters by giving them the results they think they want.
We cannot know that the leading questions had irretrievably altered the participants’ original memories.
Instead, participants could merely be following the researcher’s suggestions in both the original round of questions and the follow-up questions.
In effect, demand characteristics could be “carried forward” – as participants remembered being asked about the cars “smashing” into each other, they were prompted to say that they had seen broken glass in the follow-up study.
Independent Learning Tasks
- Draw a table showing the results of experiment one and draw a bar chart to show the results of experiment two.
- Read the original article of the study.
- Conduct your own study repeating one of the experiments by Loftus and Palmer.
- Use photographs (or video clips) of car accidents and write a set of questions, one of which will be the critical question.
- Test one group of participants using the “smashed” condition and the other group with the “hit” condition.
- Calculate the mean, median and mode speed estimates for both the “smashed” and “hit” conditions. Illustrate your results in either a table or graph.
Learning Check (1)
- Write an experimental hypothesis for experiment 1. Make sure it is clearly operationalized and include the independent and dependent variables.
- Why was it a good idea to ask 10 questions rather than just asking the critical question alone?
- Why was each group of participants shown the 7 video clips (of car accidents) in a different order?
- Outline the possible sampling technique that may have been used in this study.
- The participants knew they were taking part in a psychology experiment. How do you think this may have effected their behavior?
- Can you think of a way that this problem might of been overcome?
Learning Check (2)
- Write a null hypothesis for experiment 2. Make sure it is clearly operationalized and include the independent and dependent variables.
- What is a “control group”, and why is it necessary?
- What is an “experimental” group?
- Outline one difference between the responses given between the two experimental groups.
- Outline the quantitative measure used in this study.
Devlin Committee Report: Report of the Committee on Evidence of Identification in Criminal Cases, 1976 Cmnd 338 134/135, 42
Loftus, E. F., & Palmer, J. C. (1974). Reconstruction of auto-mobile destruction : An example of the interaction between language and memory. Journal of Verbal Learning and Verbal behavior , 13, 585-589.
Yuille, J. C., & Cutshall, J. L. (1986). A case study of eyewitness memory of a crime. Journal of Applied Psychology, 71(2), 291.
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Improving your Title Improving your Abstract If you are not sure what should be included in each summary sentence, use the following list as a guide: If your Abstract is too long, look carefully at each summary sentence and take out any information that is not essential to that section of the report. Improving your Introduction
2. give the necessary background for the scientific concept by telling what you know about it (the main references you can use are the lab manual, the textbook, lecture notes, and other sources recommended by the lab manual or lab instructor; in more advanced labs you may also be expected to cite the findings of previous scientific studies related to the lab). In relatively simple labs you can do this in a paragraph following the initial statement of the scientific concept of the lab. But in more complex labs, the background may require more paragraphs. 1. The objective(s) are what it is you are supposed to accomplish in the experimental procedure itself. The objective(s), therefore, is usually presented in terms of a specific verb that describes what you are supposed to be doing in the lab, such as to measure, to analyze, to determine, to test etc. Often, the objective(s) for the lab is given in the lab manual. If you are having trouble phrasing the sentence about objectives, try something like: "The main objectives of this lab were to "; "In this lab we were to ." 2. The purpose of the lab is different in significant ways from its objective(s). Purpose provides the wider view; it answers the why question, why you are doing the lab in the first place. Instead of focusing just on the specific actions of the experimental procedure, purpose looks at the experimental procedure within the context of what you are supposed to be learning. If you are having trouble starting the sentence about the purpose of the lab, try saying something like this: "The objectives of this lab enabled me to learn about X by "; "Performing these objectives helped me to understand X by ." To improve this part of the introduction, go back to what you have written about the scientific concept and look for a link between it and the activities you are expected to perform in the lab: what specifically about the scientific concept were these activities designed to teach you? Providing logical reasoning for the hypothesis means explaining the reasoning that you used to make your hypothesis. Usually this reasoning is based on what you know about the scientific concept of the lab and how that knowledge led you to the hypothesis. In science, you reason from what you know to what you don't know. In a couple of sentences (more for complex labs) describe the logic that you used to reason from what you know about the scientific concept to your educated guess of the outcomes of the experimental procedure. If you need to make the logic of your hypothesis clearer, use words that indicate an explanation: because, since, due to the fact that, as a result, therefore, consequently, etc. Often you can present the hypothesis and the supporting reasoning in one paragraph. In more complex labs, especially those with multiple procedures and therefore multiple hypotheses, you may need more paragraphs, perhaps one for each hypothesis. Improving your Methods A good Methods section describes what you did in the lab in a way that is easy to understand and detailed enough to be repeated. To make your Methods better, follow these guidelines: Improving your Results One of the main problems with visuals is lack of clarity. You may have chosen a form of visual that does not represent the data clearly. To see if there is a form of visual that represents the data more clearly, go to the LabWrite Graphing Resources for help. Another problem with visuals can be ascribed to lack of accuracy. Visuals are accurate when they correctly represent the data from the experiment. If there is a problem with accuracy, you should check three points at which accuracy could be jeopardized: (1) you may have recorded the raw data from the procedure incorrectly; (2) you may have entered the raw data onto the spread sheet incorrectly; and (3) you may have made careless errors in the format of the visuals, particularly in labeling the x- and y-axes and in designating the units along those axes. The presentation of findings in words should be ordered according the order of the visuals, each visual being described in words. Each description should include a sentence or so summarizing the visual and then any details from the visual pertinent to the data from that visual. To make the verbal part of your Results better, follow this general outline: Etc.The verbal representation of each visual should refer explicitly to the visual (Table 1, Figure 2, etc.). You should create the sense that the visual and the word representations of data are working together. The primary way of doing that is to cite the visuals in your verbal findings. If you had trouble integrating the verbal and the visuals, be sure you have, at a minimum, a reference to the visual in the first sentence of each paragraph when you describe the overall finding of the visual. Improving your Discussion The Discussion should start with a sentence or two in which you make a judgment as to whether your original hypothesis (from the Introduction) was supported, supported with qualifications, or not supported by the findings. To improve the opening of your Introduction, make sure your judgment is stated clearly, so that the reader can understand it. There are, generally speaking, three possible conclusions you could draw: If you had trouble composing this sentence, try being straightforward about it, for example, "The hypothesis that X solution would increase in viscosity when solutions Y and Z were added was supported by the data." Problems with the sufficiency of the explanation refer to the reader's judgment that you didn't include enough details in your explanation, that there wasn't enough of an explanation to satisfy the reader that you fully understood why the relationship between the results and hypothesis was what it was. You need to provide greater depth in your explanation. Do some brainstorming. Look again at the explanation you placed at the end of the Introduction. Jot down more details about the explanation and use those jottings to help you expand that part of the Discussion. Problems with the logic of the explanation refer to the reader's judgment that your explanation of the support or lack of support of the hypothesis did not adhere to sound scientific reasoning. Look at the reasoning you used in the explanation. It should follow one of four basic arguments: 1. If the results fully support your hypothesis and your reasoning was basically sound, then elaborate on your reasoning by showing how the science behind the experiment provides an explanation for the results. 2. If the results fully support your hypothesis but your reasoning was not completely sound, then explain why the initial reasoning was not correct and provide the better reasoning. 3. If the results generally support the hypothesis but with qualifications, then describe those qualifications and use your reasoning as a basis for discussing why the qualifications are necessary. 4. If the results do not support your hypothesis, then explain why not; consider (1) problems with your understanding of the lab's scientific concept; (2) problems with your reasoning, and/or (3) problems with the laboratory procedure itself (if there are problems of reliability with the lab data or if you made any changes in the lab procedure, discuss these in detail, showing specifically how they could have affected the results and how the errors could have been eliminated). You can also improve the logic of your explanation by using words that make your argument clear, such as , , , , , , etc. Improving your Conclusion A good Conclusion takes you back to the larger purpose of the lab as stated in the Introduction: to learn something about the scientific concept, the primary reason for doing the lab. The Conclusion is your opportunity to show your lab instructor what you learned by doing lab and writing the lab report. You can improve your Conclusion first by making a clearer statement of what you learned. Go back to the purpose of the lab as you presented it in your Introduction. You are supposed to learn something about the scientific concept or theory or principle or important scientific procedure that the lab is about. If you are not sure if you have stated what you have learned directly enough, read your first paragraph to see if your reader would have any doubt about what you have learned. If there is any doubt, you may begin the paragraph by saying something like, "In this lab, I learned that ...." Simply saying you learned something is not necessarily going to convince the reader that you actually did learn it. Demonstrate that you did indeed learn what you claimed to have learned by adding more details to provide an elaboration on the basic statement. Read over the Results and Discussion and jot down some notes for further details on what you have learned. Look carefully at the statement of what you have learned and underline any words or phrases that you could "unpack," explain in more detail. Use this brainstorming as a way of helping you to find details that make your Conclusion more convincing. If you think you need to do more to convince your reader that you have learned what you say you have learned, provide more details in the Conclusion. For example, compare what you know now with what you knew before doing the lab. Describe specific parts of the procedure or data that contributed to your learning. Discuss how you may be able to apply what you have learned in the lab to other situations in the future.
Improving the Presentation of your Report Style in this case refers to your choice of words and sentence structure. The style of science writing strives to be clear and to the point. You should avoid using grand thesaurus words and long, artfully convoluted sentences. As to choice of words, science writing uses words that its audience (other scientists in the field) will readily understand. To outsiders, the scientific vocabulary of this language looks like a lot of jargon. But the point is that scientific words that are obscure to outsiders are usually not obscure to the insiders that comprise the scientific audience. Your writing should sound like scientific writing. This means that you should go ahead and use proper scientific terminology, but you should also choose plain, everyday words for non-scientific terminology. Your sentences should be clear and readable for your educated audience. Avoid excessively long and meandering sentences. But don't use a lot of very short sentences, either. Vary your sentence length. If you have difficulties with making your sentences readable, read over them aloud, noting the sentences that seem to be too long or are hard to read. Rewrite those sentences so that they flow more easily. Also, avoid using quotations. Scientists very rarely quote from source materials; they do so only when a particular wording is important to the point they are trying to make. Using direct quotations is appropriate to English papers, but not to lab reports. It's important that you understand that the source of grammar problems is not, for most of us, a matter of not knowing the rules of grammar. So don't worry about that. The source of most grammatical errors is simply not seeing them in your own writing. We usually read our own writing for the meaning that the words convey and not for the words themselves. Correcting grammar problems, then, is usually a matter of learning to read our writing differently. Read your lab report at least twice specifically looking for errors in grammar. You should focus on the words and sentences themselves. You don't need any special knowledge for detecting and correcting most grammar problems. If you do read for error, you will probably be able to spot problems and correct them without having to look anything up in a handbook. If you feel like you do need special help with grammar, go to the "On-line Writing Handbook" on the LabWrite Resources Page. First, run the spell-checker on your computer. That should take care of almost all of your spelling problems. Sometimes, however, there are words that the spell-checker does not catch because they are words that are actually spelled correctly but are used for the wrong meaning, like using "to" for "too" and "that" for "than." You should be able to spot these misuses of words by reading over the report looking for error, as described under "grammar errors" immediately above.
Overall Aims of the Report: The student... This is, of course, the purpose for doing the lab, to learn something about the science of the course you are taking. Reading your lab report gives your teacher a good idea of how well you have achieved this all important aim. It's your job in the lab report to represent as fairly as you can what you have learned. What you have learned is indicated in the report, especially the Introduction and the Conclusion. You can improve the Introduction by (1) expressing more clearly the scientific concept you are supposed to be learning about and (2) showing that you have a good understanding of the scientific concept (see treatment of Introduction above). In addition, check your designation of the purpose of the lab in the Introduction. Be sure that it explicitly and clearly makes the connection between the objectives of the procedure and the scientific concept. The other key part of the report you should review is the Conclusion. This is where you make your strongest case for what you learned in doing the lab. You may be able to improve the Conclusion by rewriting the statement of what you have learned, revising it so that it is clearer to the reader. You could also enhance the rest of the Conclusion by adding more details concerning what you have learned (see treatment of Conclusion above). Remember, your job is to convince your reader that you have achieved the overall learning goal of the lab, and this is the section of the report in which you do that directly. One of the objects of the lab and lab report is to give you the experience of participating in scientific inquiry, the form of thinking that defines science. In other words, you need to show through the lab report that you can think like a scientist. There are key places in the report where you indicate your ability to do that. The first is found at the end of the Introduction where you present your hypothesis, which drives scientific inquiry. You can improve this part of the report by (1) restating the hypothesis so that it more clearly and more specifically presents your educated guess of the outcomes of the experimental procedure and (2) enhancing the logic that you use to show how you have reasoned from what you know about the scientific concept to your hypothesis. You may need to make the links in that logical chain clearer to the reader, or you may need to entirely rethink your reasoning (which could lead to a different hypothesis). The other place in your report in which you exhibit your ability to think scientifically is in the Discussion. That's where you come back to the hypothesis to see if it is supported or not supported by the results of the procedure. First, are you making a reasonable judgment about whether or not the hypothesis is supported by the findings? Second, do you provide clear evidence from the Results that back up your judgment? And third, do you give a sound explanation, based on your understanding of the scientific concept of the lab, for your judgment? Perhaps you need to revise your explanation so that it is more logical, provides a greater depth of discussion (more details), and treats all the facts that are relevant. Also in the Discussion you have the opportunity to compare your results to the results of others, other students in the lab or (in more sophisticated labs) published scientific studies. This is an important aspect of scientific inquiry. Look to see that you make the necessary comparisons and that your explanations for the comparisons are full and logical. There are two ways of looking at this aim, depending on the kind of lab you are in. In some labs, there is a "right answer," a specific unknown or standard measurement you are expected to find. In these cases, the emphasis of the aim is on "expected outcomes." That is, your laboratory procedure is expected to yield certain results and, to a certain extent, the quality of your work depends on whether or not you attain those results. In other labs, there may be no established outcome for the procedure, or it may be that doing the procedure in a scientifically sound way is more important than the particular answer you get. In both kinds of labs, the places where you need to focus your efforts on improvement are Methods and Results. If you need to have the right answer, then you should revisit your lab notebook to search out errors in recording data and transcribing data to spreadsheet and in any calculations you have done. You must rewrite your report accordingly. But if your aim is to demonstrate that your procedures are sound and that they legitimately lead to your results, then look at these sections of the report. Is your procedure described clearly enough? Are your results presented in sufficient detail? The point is to demonstrate that there is a clear relationship between procedure and outcomes.
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5. Phrase your hypothesis in three ways. To identify the variables, you can write a simple prediction in if…then form. The first part of the sentence states the independent variable and the second part states the dependent variable. If a first-year student starts attending more lectures, then their exam scores will improve.
Lab Report Example (Continued) Conclusion (approx. 1 paragraph) Restate your goals (In summary, the goal of this experiment was to measure…) Restate your methods (This hypothesis was tested by…) Key findings (The findings supported the hypothesis because…) Limitations (Although, certain elements were overlooked, including…)
The six steps of the scientific method include: 1) asking a question about something you observe, 2) doing background research to learn what is already known about the topic, 3) constructing a hypothesis, 4) experimenting to test the hypothesis, 5) analyzing the data from the experiment and drawing conclusions, and 6) communicating the results ...
Introduction. Your lab report introduction should set the scene for your experiment. One way to write your introduction is with a funnel (an inverted triangle) structure: Start with the broad, general research topic. Narrow your topic down your specific study focus. End with a clear research question.
There are three types of experiments you need to know: 1. Lab Experiment. A laboratory experiment in psychology is a research method in which the experimenter manipulates one or more independent variables and measures the effects on the dependent variable under controlled conditions. A laboratory experiment is conducted under highly controlled ...
Table of contents. Step 1: Define your variables. Step 2: Write your hypothesis. Step 3: Design your experimental treatments. Step 4: Assign your subjects to treatment groups. Step 5: Measure your dependent variable. Other interesting articles. Frequently asked questions about experiments.
Experimental reports (also known as "lab reports") are reports of empirical research conducted by their authors. You should think of an experimental report as a "story" of your research in which you lead your readers through your experiment. As you are telling this story, you are crafting an argument about both the validity and reliability of ...
A hypothesis proposes a relationship between the independent and dependent variable. A hypothesis is a prediction of the outcome of a test. It forms the basis for designing an experiment in the scientific method.A good hypothesis is testable, meaning it makes a prediction you can check with observation or experimentation.
A research hypothesis is a concise statement about the expected result of an experiment or project. In many ways, a research hypothesis represents the starting point for a scientific endeavor, as it establishes a tentative assumption that is eventually substantiated or falsified, ultimately improving our certainty about the subject investigated.
Author, A. A., Author, B. B., & Author, C. C. (year). Article title. Journal Title, volume number (issue number), page numbers. A simple way to write your reference section is to use Google scholar. Just type the name and date of the psychologist in the search box and click on the "cite" link. Next, copy and paste the APA reference into the ...
Step 5: Phrase your hypothesis in three ways. To identify the variables, you can write a simple prediction in if … then form. The first part of the sentence states the independent variable and the second part states the dependent variable. If a first-year student starts attending more lectures, then their exam scores will improve.
Then they formulate a hypothesis, manipulate the variables, and collect data on the results. Unrelated or irrelevant variables are carefully controlled to minimize the potential impact on the experiment outcome. ... While lab experiments are known as true experiments, researchers can also utilize a quasi-experiment. ...
Keep in mind that writing the hypothesis is an early step in the process of doing a science project. The steps below form the basic outline of the Scientific Method: Ask a Question. Do Background Research. Construct a Hypothesis. Test Your Hypothesis by Doing an Experiment. Analyze Your Data and Draw a Conclusion.
Determine what is included in your report based on the goals and purpose of your project. Discussion and Conclusion. In this section, you should analyze your results and relate your data back to your hypothesis. You should mention whether the results you obtained matched what was expected and the conclusions that can be drawn from this.
Download this page as a PDF: Writing a Lab Report. Return to Writing Studio Handouts. Part 1 (of 2): Introducing a Lab Report. The introduction of a lab report states the objective of the experiment and provides the reader with background information. State the topic of your report clearly and concisely (in one or two sentences).
A hypothesis (plural hypotheses) is a proposed explanation for an observation. The definition depends on the subject. In science, a hypothesis is part of the scientific method. It is a prediction or explanation that is tested by an experiment. Observations and experiments may disprove a scientific hypothesis, but can never entirely prove one.
A hypothesis is a tentative, testable answer to a scientific question. Once a scientist has a scientific question she is interested in, the scientist reads up to find out what is already known on the topic. Then she uses that information to form a tentative answer to her scientific question. Sometimes people refer to the tentative answer as "an ...
However, there are some important things to consider when building a compelling hypothesis. 1. State the problem that you are trying to solve. Make sure that the hypothesis clearly defines the topic and the focus of the experiment. 2. Try to write the hypothesis as an if-then statement.
Experiment Definition in Science. By definition, an experiment is a procedure that tests a hypothesis. A hypothesis, in turn, is a prediction of cause and effect or the predicted outcome of changing one factor of a situation. Both the hypothesis and experiment are components of the scientific method. The steps of the scientific method are:
There are 5 main steps in hypothesis testing: State your research hypothesis as a null hypothesis and alternate hypothesis (H o) and (H a or H 1). Collect data in a way designed to test the hypothesis. Perform an appropriate statistical test. Decide whether to reject or fail to reject your null hypothesis. Present the findings in your results ...
Experiment One: 5 verbs in leading questions. Procedure. Forty-five American students from the University of Washington formed an opportunity sample. This was a laboratory experiment with five conditions, only one of which was experienced by each participant (an independent measures experimental design).
Improving your Introduction. successfully establishes the scientific concept of the lab. To establish the scientific concept for the lab you need to do two things: 1. state what the lab is about, that is, what scientific concept (theory, principle, procedure, etc.) you are supposed to be learning about by doing the lab.
A hypothesis is the best answer to a question based on what is known. Scientists take that best answer and do experiments to see if it still makes sense or if a better answer can be made. When a scientist has a question they want to answer, they research what is already known about the topic. Then, they come up with their best answer to the ...