A large food company is considering entering the health and nutrition sector. Each of these is a separate independent variable. the mud) the outcome variable. Retrieved March 2, 2023, In this case, participation in after-school math tutoring is the independent variable. The company wants to claim that when an athlete drinks Gatorade, their performance will improve. The dependent variable would be the amount of liquid absorbed by the paper towel. by What are independent and dependent variables? They enlist the cooperation of over 120 gym rats that work out 5 days a week. Independent variables are the variables that the experimenter changes to test their dependent variable. When you collect quantitative data, the numbers you record represent real amounts that can be added, subtracted, divided, etc. Review of General Psychology, 14(2), 68-81. https://doi.org/10.1037/a0018941, Flannelly, L. T., Flannelly, K. J., & Jankowski, K. R. (2014). Is the variable one that is being manipulated by the experimenters? Example: Your test score affects how long you sleep. Variables that are held constant throughout the experiment. The amount of skull damage of dummies in cars with airbags was then compared with those without airbags. Here are the definitions for independent and dependent variables, examples of each variable, and the explanation for how to graph them. If you write out the variables in a sentence that shows cause and effect, the independent variable causes the effect on the dependent variable. The relationship makes sense and identifies the independent variable as phone use and the dependent variable as sleep quality. 2015;21(1):39-49. doi: 10.1080/08854726.2014.989799. You need to know what type of variables you are working with to choose the right statistical test for your data and interpret your results. You can apply just two levels in order to find out if an independent variable has an effect at all. Scientists want to know what causes changes in the dependent variable. Operational variables (or operationalizing definitions) refer to how you will define and measure a specific variable as it is used in your study. If you want to know whether caffeine affects your appetite, the presence/absence or amount of caffeine is the independent variable. Published on The independent variable is Mozart, and the dependent variable is exam scores. February 3, 2022 MeSH By Kendra Cherry Dr. Cornell has worked in education for more than 20 years. There are two main types of independent variables. The independent variable in your experiment would be the brand of paper towel. Required fields are marked *, This Article was Last Expert Reviewed on October 23, 2022 by Chris Drew, PhD. In this highly unrealistic study, the independent variable is vitamins, and the dependent variable is health, as measured by blood pressure and cholesterol levels. 8600 Rockville Pike 3. and transmitted securely. Published on 2018 Jan;9(1):12-21. doi: 10.1037/per0000254. https://doi.org/10.1080/08854726.2014.959374, Manocha, R., Black, D., Sarris, J., & Stough, C.(2011). All we have to do is find 90 people that are similar in age, stress levels, diet and exercise, and as many other factors as we can think of. What is the difference between discrete and continuous variables? You vary the room temperature by making it cooler for half the participants, and warmer for the other half. Selection bias occurs when the procedures used to select subjects and others factors that influence participation in the study produce a result that is different from what would have been obtained if all members of the target population were included in the study. Independent variables also have different levels. (2022, December 02). HHS Vulnerability Disclosure, Help A group of teachers is interested in which teaching method will work best for developing critical thinking skills. If you want to know whether caffeine affects your appetite, the presence/absence of a given amount of caffeine would be the independent variable. In addition, the article links terminology about variables with the concept of levels of measurement in research. Your independent variable is brand of soda . The independent variable is the teaching method, and the dependent variable is performance on the critical thinking test. Your independent variable is the treatment that you directly vary between groups. In your research design, its important to identify potential confounding variables and plan how you will reduce their impact. During the first three months of the academic year, they randomly select some 5th-grade classrooms to listen to Mozart during their lessons and exams. September 19, 2022 In an experiment, you manipulate the independent variable and measure the outcome in the dependent variable. These concepts should not be confused with predictor and outcome variables. You randomly assign your patients to one of the three groups: A true experiment requires you to randomly assign different levels of an independent variable to your participants. independent and dependent variable examples thoughtco, understanding co2 lasers, inferring from data home ubalt edu, independent variables and dependent . The determination of causality is the key benefit of manipulating the independent variable and them observing changes in the dependent variable. What type of data does the variable contain? Gatorade and Improved Athletic Performance, 15. Can I include more than one independent or dependent variable in a study? In an experiment you would control these potential confounders by holding them constant. Because the researcher controls the level of the independent variable, it can be determined if the independent variable has a causal effect on the dependent variable. In general, experiments have these three types of variables: independent, dependent, and controlled. You have three independent variable levels, and each group gets a different level of treatment. The dependent variable is the outcome (or response) variable. A variable is called dependent if a derivative of that variable occurs. 2023 Dotdash Media, Inc. All rights reserved. It represents the cause or reason for an outcome. A correlation reflects the strength and/or direction of the relationship between two (or more) variables. Here, the amount of chemical is the independent variable and the rat health is the dependent variable. The researchers then compare the scores of the exams between the two groups of classrooms. Dependent & independent variables. A confounding variable, also called a confounder or confounding factor, is a third variable in a study examining a potential cause-and-effect relationship. Information biasrefers to a systematic error due to inaccurate measurement or classification of disease, exposure, or other variables.[3] Recall bias, a type of information bias, occurs when study participants do not remember the information they report accurately or completely. In machine learning, independent variables are known as features. Categorical variables are any variables where the data represent groups. Can a variable be both independent and dependent? Other variations of an experiment might include having multiple levels of the independent variable. Distinguishing between independent and dependent variables can be tricky when designing a complex study or reading an academic research paper. This is a quasi-experimental design because theres no random assignment. For example, if you are interested in the effect of a diet on health, you can use multiple measures of health: blood sugar, blood pressure, weight, pulse, and many more. Each of these is its own dependent variable with its own research question. People who exercise regularly sleep better at night. You can email the site owner to let them know you were blocked. Are you ready to take control of your mental health and relationship well-being? If the independent variable affects the dependent variable, then it should be possible to observe changes in the dependent variable based on the presence or absence of the independent variable. You can also apply multiple levels to find out how the independent variable affects the dependent variable. For example, in an experiment about the effect of nutrients on crop growth: The independent variable is the amount of nutrients added to the crop field. His work has involved designing teacher certification for Trinity College in London and in-service training for state governments in the United States. The x-axis is the independent variable, while the y-axis is the dependent variable. The research participants are randomly assigned to either receive the independent variable (called the treatment condition), or not receive the independent variable (called the control condition). How hungry you are would be the dependent variable. When running a study or analyzing statistics, researchers try to remove or account for as many of the confounding variables as possible in their study design or analysis. Chemotherapy and Cancer A hospital is investigating the effectiveness of a new type of chemotherapy on cancer. You manipulate the independent variable (the one you think might be the cause) and then measure the dependent variable (the one you think might be the effect) to find out what this effect might be. Definition and Design, The Differences Between Explanatory and Response Variables, The Role of a Controlled Variable in an Experiment, Ph.D., Biomedical Sciences, University of Tennessee at Knoxville, B.A., Physics and Mathematics, Hastings College. Next, they randomly select university males to enter their testing facilities. Epub 2022 Mar 25. As an example, if we state that higher intelligence causes improved learning among students, then intelligence is an independent variable and learning is a dependent variable. (2010). A large multinational cosmetics company wants to know if the color of a womans hair affects the level of perceived attractiveness in males. We are committed to engaging with you and taking action based on your suggestions, complaints, and other feedback. Verywell Mind's content is for informational and educational purposes only. At the outset of an experiment, it is important for researchers to operationally define the independent variable. Each version contains a different blend of specially developed chemicals. Therefore, you could state that media violence is operationally defined (in your experiment) as exposure to a 15-minute film showing scenes of physical assault; aggression is operationally defined as levels of electrical shocks administered to a second participant in another room. For example, we might change the type of information (e.g., organized or random) given to participants to see what effect this might have on the amount of information remembered. A confounding variable in the example of car exhaust and asthma would be differential exposure to other factors that increase respiratory issues, like cigarette smoke or particulates from factories. Dr. Helmenstine holds a Ph.D. in biomedical sciences and is a science writer, educator, and consultant. For example, allocating participants to drug or placebo conditions (independent variable) to measure any changes in the intensity of their anxiety (dependent variable). How should we measure stress? sharing sensitive information, make sure youre on a federal Retrieved from https://www.thoughtco.com/independent-and-dependent-variable-examples-606828. For example, if you're studying whether a change in temperature affects productivity, the independent variable would be the room temperature, and the dependent . A confounding variable, or confounder, affects the relationship between the independent and dependent variables. Here are several examples of independent and dependent variables in experiments: In a study to determine whether how long a student sleeps affects test scores, the independent variable is the length of time spent sleeping while the dependent variable is the test score. The patients are randomly assigned to one of three groups: one group receives no chemotherapy, one group receives a low dose of chemotherapy, and one group receives a high dose of chemotherapy. Kendra Cherry, MS, is an author and educational consultant focused on helping students learn about psychology. This article begins by defining the term variable and the terms independent variable and dependent variable, providing examples of each. finishing places in a race), classifications (e.g. Your dependent variable is the brain activity response to hearing infant cries. A dependent variable is the variable that changes as a result of the independent variable manipulation. In an experiment, you manipulate the independent variable and measure the outcome in the dependent variable. In a representative example: Several crash cars were outfitted with an airbag, and an equal number were not. After many claims that listening to Mozart will make you smarter, a group of education specialists decides to put it to the test. Of course, they would prefer that consumers enter and exit quickly to increase sales volume and profit. Use this list of questions to check whether youre dealing with an independent variable: Check whether youre dealing with a dependent variable: Independent and dependent variables are generally used in experimental and quasi-experimental research. Tutors' Association ID: 55870609, Join Grad Coach On: Facebook | Twitter | YouTube | LinkedIn, Qualitative Data Analysis Methods 101: The Big 6 Methods (Including Examples), How To Write A Dissertation Or Thesis 101: Big Picture Guide (With Examples). You can usually identify the type of variable by asking two questions: Data is a specific measurement of a variable it is the value you record in your data sheet. The amount of input the workers have over their work is the independent variable in this example. Women are more attracted to men without earrings than men with earrings. In analytical health research there are generally two types of variables. Amanda Tust is a fact-checker, researcher, and writer with a Master of Science in Journalism from Northwestern University's Medill School of Journalism. About The Helpful Professor The independent variable is hair color, and the dependent variable is pupil dilation. If you want to cite this source, you can copy and paste the citation or click the Cite this Scribbr article button to automatically add the citation to our free Citation Generator. Changes in . Operationalization has the great advantage of generally providing a clear and objective definition of even complex variables. Variables that represent the outcome of the experiment. Predictor variables (they can be used to predict the value of a dependent variable), Right-hand-side variables (they appear on the right-hand side of a, Outcome variables (they represent the outcome you want to measure), Left-hand-side variables (they appear on the left-hand side of a regression equation). The dependent variable (height) depends on the independent variable (age). In this animal study, the independent variable would be car exhaust and the dependent variable would be amount of time to run a maze. Choosing which variables to measure is central to good experimental design. Independent vs. Each shopper is given a box of the same food and drink items and sent to one of the rooms. Groups with no rank or order between them. Some examples of variables that you may need to control include: Temperature Time of day Lighting Stress Noise or distractions Which specific variables need to be controlled for will vary tremendously depending on the research project at hand, so there's no generic list of control variables to consult. A well-known fast-food corporation wants to know if the color of the interior of their restaurants will affect how fast people eat. Can graphic video games be a force for good? In other cases, multiple levels of the IV may be used to look at the range of effects that the variable may have. Why are independent and dependent variables important? Some useful types of variables are listed below. Is medical marijuana effective for pain reduction in people with chronic pain? Blazing Angels or Resident Evil? Accessibility Bhandari, P. In this natural experiment, a community living near higher concentrations of car exhaust may also live near factories that pollute or have higher rates of smoking. 3. Click to reveal While the study participants are sleeping, their heart rates and amount of time spent in deep sleep are recorded with high-tech equipment. They randomly assign half of the participants to take the recommended dosage of their supplement every day for three months after each workout. Difference Between Independent and Dependent Variables, Dependent Variable Definition and Examples, Independent Variable Definition and Examples, What Is an Experiment? In this study, despite the ethical issues (remember this is just a hypothetical example), the independent variable is chemotherapy, and the dependent variable is tumor size. Each of these types of variables can be broken down into further types. In a study to determine whether how long a student sleeps affects test scores, the independent variable is the length of time spent sleeping while the dependent variable is the test score. Unauthorized use of these marks is strictly prohibited. [8] Examples of these variables include: You can think of independent and dependent variables in terms of cause and effect: an. 2022 Aug;27(5):436-446. doi: 10.1177/17449871211051566. Plausible alternative explanations are other factors that may cause the dependent variable under observation.[4]. This website is using a security service to protect itself from online attacks. Note that any research methods that use non-random assignment are at risk for research biases like selection bias and sampling bias. The PubMed wordmark and PubMed logo are registered trademarks of the U.S. Department of Health and Human Services (HHS). Your email address will not be published. official website and that any information you provide is encrypted Because it would be unethical to expose a randomized group of people to high levels of vehicle exhaust,[1] a study comparing two populations with differential exposure to vehicle exhaust would rely on a natural experiment, or a situation in which this already occurs due to factors unrelated to the researchers.