Why are independent and dependent variables important? Once you have defined your independent and dependent variables and determined whether they are categorical or quantitative, you will be able to choose the correct statistical test. Dr. Cornell has worked in education for more than 20 years. Studentsshould always cross-check any information on this site with their course teacher. 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). PMC Definition and examples of dependent variable Independent variables are the ones we can freely manipulate, by plugging in any input value. The independent variable (IV) in psychology is the characteristic of an experiment that is manipulated or changed by researchers, not by other variables in the experiment. Plausible alternative explanations are other factors that may cause the dependent variable under observation.[4]. Examples of Independent and Dependent Variables in Experiments The health of the rat (whether it lives and can reproduce) is the dependent In quantitative research, its good practice to use charts or graphs to visualize the results of studies. In an experiment you would control these potential confounders by holding them constant. Can a variable be both independent and dependent? The determination of causality is the key benefit of manipulating the independent variable and them observing changes in the dependent variable. This is because individuals that had a particularly bad (or good) experience with the physician may be more likely to go to the website and provide a rating. In an experiment to determine how far people can see into the infrared part of the spectrum, the wavelength of light is the independent variable and whether the light is observed (the response) is the dependent variable. You have three independent variable levels, and each group gets a different level of treatment. The dependent variable (height) depends on the independent variable (age). Of course, they would prefer that consumers enter and exit quickly to increase sales volume and profit. Brain morphology, harm avoidance, and the severity of excessive internet use. Each athlete will run on a treadmill for one hour while their heart rate is tracked. Careers, National Center for Biotechnology Information, Lister Hill National Center for Biomedical Communications, Agency for Healthcare Research and Quality, Centers for Disease Control and Prevention, Robert Wood Johnson Foundation County Health Rankings & Roadmaps, Centers for Medicare and Medicaid Services. For example, star ratings on product reviews are ordinal (1 to 5 stars), but the average star rating is quantitative. Its essential to know which is the cause the independent variable and which is the effect the dependent variable. The independent variable is Mozart, and the dependent variable is exam scores. It can be difficult to separate the true effect of the independent variable from the effect of the confounding variable. In this highly unrealistic study, the independent variable is vitamins, and the dependent variable is health, as measured by blood pressure and cholesterol levels. Independent and Dependent Variables: Differences & Examples The independent variable is the variable the experimenter manipulates or changes, and is assumed to have a direct effect on the dependent variable. If you write out the variables in a sentence that shows cause and effect, the independent variable causes the effect on the dependent variable. A variable is called dependent if a derivative of that variable occurs. Educators are interested in whether participating in after-school math tutoring can increase scores on standardized math exams. The brand of popcorn is the independent variable. It then proceeds to describe and discuss synonyms for the terms independent variable and dependent variable, including treatment, intervention, predictor, and risk factor, and synonyms for dependent variable, such as response variables and outcomes. Nominal and categorical variables describe samples in groups based on counts that fall within each category, have no quantitative relationships, and cannot be ranked. How hungry you are would be the dependent variable. https://doi.org/10.1080/08854726.2014.959374, Manocha, R., Black, D., Sarris, J., & Stough, C.(2011). The brand of fertilizer is the independent variable. A well-known fast-food corporation wants to know if the color of the interior of their restaurants will affect how fast people eat. 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. The https:// ensures that you are connecting to the A researcher wants to determine if the color of an office has any effect on worker productivity. At the end of the study, the researchers compare the total amount of time spent in deep sleep of the lavender-room participants with the no lavender-room participants. Stressful experiences significantly increase the likelihood of headaches. ____________________________________________________________. A dependent variable is a variable whose value depends upon independent variable s. The dependent variable is what is being measured in an experiment or. Subscribe now and start your journey towards a happier, healthier you. If they can back up that claim with hard scientific data, that would be great for sales. If you want to test whether some plant species are more salt-tolerant than others, some key variables you might measure include the amount of salt you add to the water, the species of plants being studied, and variables related to plant health like growth and wilting. [2] For example, an online website that rates the quality of primary care physicians based on patients input may produce ratings that suffer from selection bias. Weiten, W. Psychology: Themes and Variations, 10th ed. Select independent variables that you think will cause changes in another variable. Because the scientists have an unlimited budget (and because this is a hypothetical example, all of the participants have the same meals delivered to their homes (breakfast, lunch, and dinner), every day for one year. If you have ever wondered if this is true or not, then you are in luck because there is a way to know one way or the other. Some people take vitamins every day. 2023 Simply Psychology - Study Guides for Psychology Students. Its called independent because its not influenced by any other variables in the study. 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. If you have the variables in the wrong order, the sentence won't make sense. 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. Although there are many types of bias, two common types are selection bias and information bias. clearly understand what a pharmacy technician can do under their own authority as a regulated health care professional, a properly designed customer satisfaction or customer The independent variable is the aspect of the situation that changes in an experiment, while the dependent variable is the predicted outcome that results from the independent variable. A group of health scientists decides to conduct a study to determine if taking vitamins improves health. It also makes it easier for other researchers to replicate a study and check for reliability. There can be all different types of independent variables. In this issue of Anesthesia & Analgesia, Mller-Wirtz et al 1 report results of a study in which they used linear regression to assess the relationship in a rat model between tissue propofol . The independent variable is one that the researchers either manipulate (such as the amount of something) or that already exists but is not dependent upon other variables (such as the age of the participants). The independent variable in this sleep study is lavender, and the dependent variable is the total amount of time spent in deep sleep. brands of cereal), and binary outcomes (e.g. An example of a dependent variable is depression symptoms, which depend on the independent variable (type of therapy). But before we begin, we need to briefly review the difference between independent and dependent variables. Can graphic video games be a force for good? The independent variable is the supplement, and the dependent variable is muscle mass. You want to compare brands of paper towels, to see which holds the most liquid. A large food company is considering entering the health and nutrition sector. The independent variable was the airbag and the dependent variable was the amount of skull damage. In this example, the color of the office is the independent variable. Scientists want to know what causes changes in the dependent variable. Vehicle Exhaust and Cognitive Performance, Mastery Learning: 10 Examples, Strengths & Limitations. It further explains that even though intervening, mediating, and moderating variables explicitly alter the relationship between independent variables and dependent variables, they help to explain the causal relationship between them. They fill each mold with one of the different concrete mixtures. Car pollution is a concern for a lot of reasons. Learn more about our academic and editorial standards. Kendra Cherry, MS, is an author and educational consultant focused on helping students learn about psychology. sharing sensitive information, make sure youre on a federal Non-manipulation quantitative designs. Blazing Angels or Resident Evil? (2010). A business wants to determine if giving employees more control over how to do their work leads to increased job satisfaction. The water temperature is the independent variable. If you have the variables in the wrong order, the sentence won't make sense. Independent and Dependent Variable Examples, How to Tell the Independent and Dependent Variable Apart. Before The company has prepared three versions of their crust that vary in crunchiness, they are: a little crunchy, very crunchy, and super crunchy. At first, many people in the industry didnt think airbags would be effective at all. 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. Design approaches to experimental mediation. In an experiment, some volunteers receive the new treatment, another group receives a different treatment, and a third group receives no treatment. Pritha Bhandari. It must be either the cause or the effect, not both! There are several actions that could trigger this block including submitting a certain word or phrase, a SQL command or malformed data. At the end of three months, the muscle mass of all participants is measured. An example of a dependent variable is depression symptoms, which depends on the independent variable (type of therapy). Variables are given a special name that only applies to experimental investigations. This website is using a security service to protect itself from online attacks. 2008;14(1):3-19. doi: 10.1080/08854720802053796. How many minutes or hours of television a person watches is the dependent variable. An example of a dependent variable is how tall you are at different ages. A randomized, controlled trial of meditation for work stress, anxiety and depressed mood in full-time workers. Be careful with these, because confounding variables run a high risk of introducing a variety of. The dependent variable is the volume of liquid absorbed by the paper towel. Bevans, R. You want to know which brand of fertilizer is best for your plants. https://helpfulprofessor.com/independent-and-dependent-variable-examples/. 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. An operational definition describes exactly what the independent variable is and how it is measured. You have three independent variable levels, and each group gets a different level of treatment. finishing places in a race), classifications (e.g. . This is a quasi-experimental design because theres no random assignment. A large multinational cosmetics company wants to know if the color of a womans hair affects the level of perceived attractiveness in males. 1 For example, in a study looking at how tutoring impacts test scores, the dependent variable would be the participants' test scores since that is what is being measured. An independent variable is the variable you manipulate, control, or vary in an experimental study to explore its effects. To understand this concept, it's helpful to take a look at the independent variable in research examples. You can think of independent and dependent variables in terms of cause and effect: an. A dependent variable is the variable that changes as a result of the independent variable manipulation. Bhandari, P. SPICE (Setting, Perspective, Intervention/phenomenon of Interest, Comparison, Evaluation) Appropriate for : evaluating the outcomes of a service, project, or intervention In these experimental studies, the independent variable was graphic video games, and the dependent variable was observed level of aggression. I.V. In other cases, researchers might find that changes in the independent variables have no effect on the variables that are being measured. The independent variable is the teaching method, and the dependent variable is performance on the critical thinking test. 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. Relate post: Effect Sizes in Statistics Variables you manipulate in order to affect the outcome of an experiment. Groups that are ranked in a specific order. Based on your findings, you can estimate the degree to which your independent variable variation drives changes in your dependent variable. Saul Mcleod, Ph.D., is a qualified psychology teacher with over 18 years experience of working in further and higher education. Researchers are trying to determine if changes to the independent variable (studying) result in significant changes to the dependent variable (the test results). For example, if we want to explore whether high concentrations of vehicle exhaust impact incidence of asthma in children, vehicle exhaust is the independent variable while asthma is the dependent variable. Epub 2016 Mar 24. Dependent & independent variables. A sports medicine researcher has been hired by Gatorade to test the effects of its sports drink on athletic performance. You use this measurement data to check whether and to what extent your independent variable influences the dependent variable by conducting statistical analyses. These variables are created when you analyze data, not when you measure it. After many claims that listening to Mozart will make you smarter, a group of education specialists decides to put it to the test. February 3, 2022 Well, there are a lot of ways. Here, the amount of chemical would be the independent variable and the rat health would be the dependent variable. Women are more attracted to men without earrings than men with earrings. They hire a sleep research lab to conduct the study. https://doi.org/10.1080/08854726.2014.959374, https://doi.org/10.1080/10790195.2012.10850354. A hospital is investigating the effectiveness of a new type of chemotherapy on cancer. Taylor, J. M., & Rowe, B. J. A correlational research design investigates relationships between variables without the researcher controlling or manipulating any of them. Epub 2021 Oct 25. You can think of independent and dependent variables in terms of cause and effect: an independent variable is the variable you think is the cause, while a dependent variable is the effect. A Dependent variable is what happens as a result of the independent variable. The amount of salt added to each plants water. The temperature and light in the room the plants are kept in, and the volume of water given to each plant. Youll often use t tests or ANOVAs to analyze your data and answer your research questions. Test your understanding with the scientific method quiz. Operational variables (or operationalizing definitions) refer to how you will define and measure a specific variable as it is used in your study. 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. Come up with a. Revised on We are committed to engaging with you and taking action based on your suggestions, complaints, and other feedback. 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). You vary the room temperature by making it cooler for half the participants, and warmer for the other half. While the study participants are sleeping, their heart rates and amount of time spent in deep sleep are recorded with high-tech equipment. Educators, social scientists, and parents were shocked at how graphic games were becoming. In this animal study, the independent variable would be car exhaust and the dependent variable would be amount of time to run a maze. Although two variables may be correlated, this does not imply that there is a causal relationship between them. This example sheet is color-coded according to the type of variable: nominal, continuous, ordinal, and binary. Does this variable come before the other variable in time? For example, if you're studying whether a change in temperature affects productivity, the independent variable would be the room temperature, and the dependent . You think rising sea temperatures might affect the amount of algae in the water. This makes sense, but: Example: Your test score affects how long you sleep. Sometimes varying the independent variables will result in changes in the dependent variables. The different levels of the independent variable are called conditions. In a representative example: Several crash cars were outfitted with an airbag, and an equal number were not. Participants aged between 16 30 will recall significantly more nouns from a list of twenty than participants aged between 55 70 is operationalized. If, say, y = x+3, then the value y can have depends on what the value of x is. Your independent variable is the treatment that you directly vary between groups. 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. The action you just performed triggered the security solution. Types of Variables in Research & Statistics | Examples. Their muscle mass is measured, and only those with a lower level are selected for the study, leaving a total of 80 study participants. To ensure cause and effect are established, it is important that we identify exactly how the independent and dependent variables will be measured; this is known as operationalizing the variables. Experiments have two fundamental features. This article was peer-reviewed and edited by Chris Drew (PhD). The .gov means its official.