The independent variable and dependent variable are used in a very specific type of scientific study called the experiment. Here the independent variable is the dose and the dependent variable is the frequency/intensity of symptoms . Retrieved March 2, 2023, A confounding variable is related to both the supposed cause and the supposed effect of the study. To ensure the internal validity of an experiment, you should only change one independent variable at a time. brands of cereal), and binary outcomes (e.g. 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. This includes rankings (e.g. You will probably also have variables that you hold constant (control variables) in order to focus on your experimental treatment. The independent variable in this example is the type of therapy. 2019;10(1):82-86. doi:10.4103/idoj.IDOJ_468_18. (2012). Discrete and continuous variables are two types of quantitative variables: 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. You measure the math skills of all participants using a standardized test and check whether they differ based on room temperature. It must be either the cause or the effect, not both! Variables you manipulate in order to affect the outcome of an experiment. Examples of Independent and Dependent Variables in Experiments When you do correlational research, the terms dependent and independent dont apply, because you are not trying to establish a cause and effect relationship (causation). Below is an example of using independent and dependent variables in an ecological study: A government agency handles environmental care in a city. A company that specializes in essential oils wants to examine the effects of lavender on sleep quality. These variables are created when you analyze data, not when you measure it. She has taught science courses at the high school, college, and graduate levels. These alternative explanations are closely related to the concept of internal validity. You can also predict how much your dependent variable will change as a result of variation in the independent variable. By contrast, the independent variable is the potential answer as to what is causing the change in the dependent variable. The researchers believe that larger dilation indicates greater perceived attractiveness. Doing this helps ensure that the experiments know exactly what they are looking at or manipulating, allowing them to measure it and determine if it is the IV that is causing changes in the DV. Since then, there have been hundreds of studies conducted by psychologists and other researchers. You want to know which brand of microwave popcorn pops the best. December 2, 2022. In an experiment, some volunteers receive the new treatment, another group receives a different treatment, and a third group receives no treatment. Changes in . What is the effect of intermittent fasting on blood sugar levels? For example, allocating participants to drug or placebo conditions (independent variable) to measure any changes in the intensity of their anxiety (dependent variable). In this example, the independent variable is Gatorade, and the dependent variable is heart rate. How hungry you are would be the dependent variable. Car pollution is a concern for a lot of reasons. A variable is called dependent if a derivative of that variable occurs. 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). You have three independent variable levels, and each group gets a different level of treatment. Although two variables may be correlated, this does not imply that there is a causal relationship between them. Of course, you could also measure the number of unpopped kernels instead. Here, the amount of chemical is the independent variable and the rat health is the dependent variable. 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 is the dependent variable. In statistics, dependent variables are also called: The dependent variable is what you record after youve manipulated the independent variable. FOIA Each athlete will run on a treadmill for one hour while their heart rate is tracked. Each group receives chemotherapy treatment three times a week for two months, except for the no-treatment group. Although there are a lot of obvious limitations to this hypothetical, it is the first step. So, first, they go to a nearby school in a middle-class neighborhood. Two other kinds of variables that might influence the outcome include: Extraneous variables can also include demand characteristics (which are clues about how the participants should respond) and experimenter effects (which is when the researchers accidentally provide clues about how a participant will respond). BSc (Hons), Psychology, MSc, Psychology of Education. Each type of diet that the experimenters look at would be a different level of the independent variable while weight loss would always be the dependent variable. 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. All the advice on this site is general in nature. Bethesda, MD 20894, Web Policies Look at other experiments for examples and identify different types of independent variables. Experiments have two fundamental features. PMC Can graphic video games be a force for good? It is the main point of focus in the experiment whereby researchers are looking to find a cause to. His work has involved designing teacher certification for Trinity College in London and in-service training for state governments in the United States. Click to reveal How many minutes or hours of television a person watches is the dependent variable. Based on your findings, you can estimate the degree to which your independent variable variation drives changes in your dependent variable. All articles are edited by a PhD level academic. Sometimes the dependent variable is called the "responding variable.". They hire a sleep research lab to conduct the study. The temperature and light in the room the plants are kept in, and the volume of water given to each plant. Each version contains a different blend of specially developed chemicals. Is the variable one that is being manipulated by the experimenters? What is the difference between quantitative and categorical variables? Other types of variables have interchangeable terms. Disclaimer. J Health Care Chaplain. 2008;14(1):3-19. doi: 10.1080/08854720802053796. Of course, they would prefer that consumers enter and exit quickly to increase sales volume and profit. The health of the plants (height, amount and size of flowers and fruit, color) is the dependent variable. Revised on The independent variable is Mozart, and the dependent variable is exam scores. Dr. Drew has published over 20 academic articles in scholarly journals. In a representative example: Several crash cars were outfitted with an airbag, and an equal number were not. In these cases you may call the preceding variable (i.e., the rainfall) the predictor variable and the following variable (i.e. For example, star ratings on product reviews are ordinal (1 to 5 stars), but the average star rating is quantitative. The independent variable was the airbag and the dependent variable was the amount of skull damage. February 3, 2022 National Library of Medicine. A variable that hides the true effect of another variable in your experiment. This article begins by defining the term variable and the terms independent variable and dependent variable, providing examples of each. The independent variable is the color of the room, and the dependent variable is the amount of time spent in the room eating. Other research methodologies can reveal factors that are related to the dependent variable or associated with the dependent variable, but only when the independent variable is controlled by the researcher can causality be determined. In statistics, dependent variables are also called: Response variables (they respond to a change in another variable) However, there might be cases where one variable clearly precedes the other (for example, rainfall leads to mud, rather than the other way around). Non-manipulation quantitative designs. Sometimes varying the independent variables will result in changes in the dependent variables. J Exp Soc Psychol. You need to know which types of variables you are working with in order to choose appropriate statistical tests and interpret the results of your study. Independent variables also have different levels. 2. You have three independent variable levels, and each group gets a different level of treatment. Please include what you were doing when this page came up and the Cloudflare Ray ID found at the bottom of this page. Whats the definition of a dependent variable? 3. They randomly assign half of the participants to take the recommended dosage of their supplement every day for three months after each workout. It then proceeds to describe and discuss synonyms for the terms independent variable and dependent variable, including treatment, intervention, predictor, and risk Identifying independent vs. dependent variables, Independent and dependent variables in research, Visualizing independent and dependent variables, Frequently asked questions about independent and dependent variables. Can graphic video games be a force for good? Categorical variables represent groupings of some kind. _________________________________________________________, D.V. Subscribe now and start your journey towards a happier, healthier you. An independent variable is the variable you manipulate or vary in an experimental study to explore its effects. Kendra Cherry, MS, is an author and educational consultant focused on helping students learn about psychology. Quantitative Data Analysis 101: Methods, Techniques & Terminology Explained. 4. BSc (Hons) Psychology, MRes, PhD, University of Manchester. If they can back up that claim with hard scientific data, that would be great for sales. In addition, the article links terminology about variables with the concept of levels of measurement in research. Kaliyadan F, Kulkarni V. Types of variables, descriptive statistics, and sample size. The presence/absence of the chemical is the independent variable. Epub 2022 Mar 25. A change in the independent variable directly causes a change in the dependent . To understand this concept, it's helpful to take a look at the independent variable in research examples. Next, they randomly select shoppers on Saturdays and Sundays to eat for free in one of the three rooms. Your IP: At the end of one year, the health of all participants is assessed, using blood pressure and cholesterol level as the key measurements. Brain morphology, harm avoidance, and the severity of excessive internet use. Saul Mcleod, Ph.D., is a qualified psychology teacher with over 18 years experience of working in further and higher education. This article was peer-reviewed and edited by Chris Drew (PhD). 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. Its the outcome youre interested in measuring, and it depends on your independent variable. I.V._____________________________________________________________, D.V. In most math . There are two types of quantitative variables: discrete and continuous. In this case, we must state what we mean by the terms media violence and aggression as we will study them. The independent variable in this sleep study is lavender, and the dependent variable is the total amount of time spent in deep sleep. J Res Nurs. A dependent variable is what changes as a result of the independent variable manipulation in experiments. The presence/absence of the chemical is the independent variable. Helmenstine, Anne Marie, Ph.D. "What Are Independent and Dependent Variables?" Your independent variable is a subject variable, namely the gender identity of the participants. The term causation is vitally important. People learn more when they study in a quiet versus noisy place. 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. independent and dependent variable examples thoughtco, understanding co2 lasers, inferring from data home ubalt edu, independent variables and dependent . One common way of assessing cognitive performance in laboratory rats is by measuring the amount of time it takes to run a maze successfully. In statistical research, a variable is defined as an attribute of an object of study. A follow-up experiment might determine how much of the chemical is needed. National Library of Medicine by The company approaches several gyms near its headquarters. It represents the cause or reason for an outcome. 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 want to determine whether a chemical is essential for rat nutrition, so you design an experiment. Definition and examples of dependent variable Independent variables are the ones we can freely manipulate, by plugging in any input value. At the same time, software on the computer that utilizes the computers camera is measuring each males pupil dilation. In addition to being bad for the environment, car exhaust may cause damage to the brain and impair cognitive performance. The other variables in the sheet cant be classified as independent or dependent, but they do contain data that you will need in order to interpret your dependent and independent variables. The research would look something like this: laboratory rats would be raised in three different rooms that varied in the degree of car exhaust circulating in the room: no exhaust, little exhaust, or a lot of exhaust. 3. Retrieved from https://www.thoughtco.com/independent-and-dependent-variable-examples-606828. *Note that sometimes a variable can work as more than one type! Personal Disord. If you are having a hard time identifying which variable is the independent variable and which is the dependent variable, remember the dependent variable is the one affected by a change in the independent variable. All of the athletes are given the exact same amount of liquid to consume 30-minutes before and during their run. The water temperature is the independent variable. The independent variable is the cause, and the dependent variable is the effect. Groups that are ranked in a specific order. Be careful with these, because confounding variables run a high risk of introducing a variety of. Dependent variable Definition and Examples. You could also choose to look at the effect of exercise levels as well as diet, or even the additional effect of the two combined. 2018 Jan;9(1):12-21. doi: 10.1037/per0000254. 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. Amanda Tust is a fact-checker, researcher, and writer with a Master of Science in Journalism from Northwestern University's Medill School of Journalism. Example: How long you sleep (independent variable) affects your test score (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. [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. Linear regression is used to quantify the relationship between 1 independent (predictor) variables and a continuous dependent (outcome) variable. Copyright 2023 Helpful Professor. The researchers identified 120 patients with relatively similar types of cancerous tumors in both size and stage of progression. Expected to influence the dependent variable, Doesn't change as a result of the experiment, Can be manipulated by researchers in order to study the dependent variable, Expected to be affected by the independent variable, Expected to change as a result of the experiment, Not manipulated by researchers; its changes occur as a result of the independent variable. By clicking Accept All Cookies, you agree to the storing of cookies on your device to enhance site navigation, analyze site usage, and assist in our marketing efforts. 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. Careers. Clarify mathematic question In mathematics, an equation is a statement that two things are equal. How someones age impacts their sleep quality, How different teaching methods impact learning outcomes. Performance & security by Cloudflare. , Independent and Dependent Variables Examples, Free Printable Periodic Tables (PDF and PNG), Periodic Table with Charges - 118 Elements, Periodic Table For Kids With 118 Elements. The health of the rat (whether it lives and can reproduce) is the dependent variable. 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. The review process on Helpful Professor involves having a PhD level expert fact check, edit, and contribute to articles. An operational definition describes exactly what the independent variable is and how it is measured. 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. and transmitted securely. Any measurement of plant health and growth: in this case, plant height and wilting. 2016 Sep;66:29-38. doi: 10.1016/j.jesp.2015.09.012. 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. The mass of algae is the dependent variable. Each participant sits in front of a computer screen and responds to questions on a survey. https://helpfulprofessor.com/independent-and-dependent-variable-examples/. Generally, the independent variable goes on the x-axis (horizontal) and the dependent variable on the y-axis (vertical). We are committed to engaging with you and taking action based on your suggestions, complaints, and other feedback. Pot size and soil type might affect plant survival as much or more than salt additions. A variable that is made by combining multiple variables in an experiment. The company wants to claim that when an athlete drinks Gatorade, their performance will improve. To what extent does remote working increase job satisfaction? Fact checkers review articles for factual accuracy, relevance, and timeliness. Rumrill, P. D., Jr. (2004). 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. Journal of Health Care Chaplaincy, 20(4), 161170. 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. What is an example of an independent and a dependent variable? by In a well-designed experimental study, the independent variable is the only important difference between the experimental (e.g., treatment) and control (e.g., placebo) groups. How do we define young, old, or memory? the mud) the outcome variable. Are researchers trying to identify how the variable influences another variable? Do not confuse it with a "control variable," which is a variable that is purposely held constant so that it can't affect the outcome of the experiment. You plot bars for each treatment group before and after the treatment to show the difference in blood pressure. You record brain activity with fMRI scans when participants hear infant cries without their awareness. Published on Weiten, W. Psychology: Themes and Variations, 10th ed. 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. Number of different tree species in a forest, Rating scale responses in a survey, such as. The independent variable in your experiment would be the brand of paper towel. Quantitative variables are any variables where the data represent amounts (e.g. Dependent and Independent variables Example of Denominator In p = 4q, p is the dependent variable, because its value depends on the value of q. So, they train a group of teachers in three different teaching styles: teacher-centered, where the teacher tells the students all about critical thinking; student-centered, where the students practice critical thinking and receive teacher feedback; and AI-assisted teaching, where the teacher uses a special software program to teach critical thinking. 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. So, they use Photoshop to manipulate the same image of a female by altering the color of her hair: blonde, brunette, red, and brown. For example, economists may want to find out what . Lack of sleep significantly affects learning in 10-year-old boys. Chemotherapy and Cancer A hospital is investigating the effectiveness of a new type of chemotherapy on cancer. 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. In this study, the independent variable is the concrete mixture, and the dependent variable is the amount of weight at collapse. Variables that are held constant throughout the experiment. At the end of the survey, the screen shows one of the photos of the female. One of the most popular forms of regression analysis is linear regression, which allows you to establish a linear relationship between a dependent variable and one or more independent variables. Do tomatoes grow fastest under fluorescent, incandescent, or natural light? 2011, Article ID 960583. https://doi.org/10.1155/2011/960583. For example, gender identity, ethnicity, race, income, and education are all important subject variables that social researchers treat as independent variables. He is the former editor of the Journal of Learning Development in Higher Education and holds a PhD in Education from ACU. Your independent variable is brand of soda . Is this variable measured as an outcome of the study? By Kendra Cherry Independent vs. official website and that any information you provide is encrypted Educators, social scientists, and parents were shocked at how graphic games were becoming. Your dependent variable is math test scores. The independent variable is usually applied at different levels to see how the outcomes differ. In this highly unrealistic study, the independent variable is vitamins, and the dependent variable is health, as measured by blood pressure and cholesterol levels. government site. In an experiment you would control these potential confounders by holding them constant. Wan L, Zha R, Ren J, Li Y, Zhao Q, Zuo H, Zhang X. Hum Brain Mapp. For example, scientists can learn if graphic video games make people more aggressive, if mediation reduces stress, if Gatorade improves athletic performance, and even if certain medical treatments can cure cancer. The independent variable is the condition that you change in an experiment. What part of the experiment does the variable represent? Stressful experiences significantly increase the likelihood of headaches. At the end of three months, the muscle mass of all participants is measured. In an experiment, the researcher looks for the possible effect on the dependent variable that might be caused by changing the independent variable. This is different than the independent variable in an experiment, which is a variable . Design approaches to experimental mediation. Researchers want to determine if a new type of treatment will lead to a reduction in anxiety for patients living with social phobia. You can use the DRY MIX acronym to help remember how to graph variables: D= dependent variableR= responding variableY= graph on the vertical or y-axis, M= manipulated variableI= independent variableX= graph on the horizontal or x-axis. Data is generally divided into two categories: A variable that contains quantitative data is a quantitative variable; a variable that contains categorical data is a categorical variable. Thank you, {{form.email}}, for signing up. In an experiment, you manipulate the independent variable and measure the outcome in the dependent variable. 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. It would also be possible to examine the physical effects of car exhaust on the brain by conducting an autopsy. Indian Dermatol Online J. What are independent and dependent variables? Type of light the tomato plant is grown under, Presence or absence of intermittent fasting, Presence or absence of medical marijuana use, Type of work environment (remote or in office). Dave Cornell (PhD) and Peer Reviewed by Chris Drew (PhD), Definition of Independent and Dependent Variables, Examples of Independent and Dependent Variables, 1. In your research design, its important to identify potential confounding variables and plan how you will reduce their impact. Dr. Cornell has worked in education for more than 20 years. If you have the variables in the wrong order, the sentence won't make sense. In this study, the independent variable is meditation and the dependent variable is the amount of stress (however it is measured). from https://www.scribbr.com/methodology/independent-and-dependent-variables/, Independent vs. Would you like email updates of new search results? The researchers identified 120 patients with relatively similar types of cancerous tumors in both size and stage of progression. 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. The dependent variable is the response that is measured. Some useful types of variables are listed below. The type of visualization you use depends on the variable types in your research questions: To inspect your data, you place your independent variable of treatment level on the x-axis and the dependent variable of blood pressure on the y-axis. A dependent variable is the variable that changes as a result of the independent variable manipulation. Required fields are marked *, This Article was Last Expert Reviewed on October 23, 2022 by Chris Drew, PhD. They fill each mold with one of the different concrete mixtures. For example, in an experiment looking at the effects of studying on test scores, studying would be the independent variable.