At the end of three months, the muscle mass of all participants is measured. So many studies have used so many different ways of measuring aggression. Example: Your test score affects how long you sleep. Be careful with these, because confounding variables run a high risk of introducing a variety of. 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. The Mozart Effect and the mathematical connection, Journal of College Reading and Learning, 42(2), 51-66. https://doi.org/10.1080/10790195.2012.10850354. Researchers often manipulate or measure independent and dependent variables in studies to test cause-and-effect relationships. 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. Independent and Dependent Variable Examples The presence/absence of the chemical is the independent variable. A large food company is considering entering the health and nutrition sector. December 2, 2022. If you write out the variables in a sentence that shows cause and effect, the independent variable causes the effect on the dependent variable. 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. Both the independent variable and dependent variable are examined in an experiment using the scientific method, so it's important to know what they are and how to use them. Revised on 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. How many minutes or hours of television a person watches is the dependent variable. Design approaches to experimental mediation. A randomized, controlled trial of meditation for work stress, anxiety and depressed mood in full-time workers. Experiments are usually designed to find out what effect one variable has on another in our example, the effect of salt addition on plant growth. If you want to know whether caffeine affects your appetite, the presence/absence of a given amount of caffeine would be the independent variable. There are several actions that could trigger this block including submitting a certain word or phrase, a SQL command or malformed data. Select independent variables that you think will cause changes in another variable. Work (Reading, Mass. What is an example of an independent and a 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. Accessibility They randomly assign half of the participants to take the recommended dosage of their supplement every day for three months after each workout. Helmenstine, Anne Marie, Ph.D. "What Are Independent and Dependent Variables?" Next, they randomly select shoppers on Saturdays and Sundays to eat for free in one of the three rooms. [8] Examples of these variables include: A hospital is investigating the effectiveness of a new type of chemotherapy on cancer. Each participant sits in a booth and takes a bite of one version of the crust. Accessibility Its essential to know which is the cause the independent variable and which is the effect the dependent variable. FOIA Thank you, {{form.email}}, for signing up. Your dependent variable is math test scores. In this case, participation in after-school math tutoring is the independent variable. J Res Nurs. The independent variable was the airbag and the dependent variable was the amount of skull damage. 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. You use this measurement data to check whether and to what extent your independent variable influences the dependent variable by conducting statistical analyses. A follow-up experiment might determine how much of the chemical is needed. Bhandari, P. Sometimes the dependent variable is called the "responding variable.". In an experiment, one group of workers performs a task in a yellow room while another performs the same task in a blue room. The different levels of the independent variable are called conditions. Dr. Drew has published over 20 academic articles in scholarly journals. 4. Is the variable something that cannot be changed but that is not dependent on other variables in the experiment? . You plot bars for each treatment group before and after the treatment to show the difference in blood pressure. BSc (Hons), Psychology, MSc, Psychology of Education. HHS Vulnerability Disclosure, Help We could measure blood pressure, or the amount of the stress hormone cortisol in their blood, or by using a paper and pencil measure such as a questionnaire that asks them how much stress they feel. Vehicle Exhaust and Cognitive Performance, Mastery Learning: 10 Examples, Strengths & Limitations. The brand of fertilizer is the independent variable. A sports medicine researcher has been hired by Gatorade to test the effects of its sports drink on athletic performance. A business wants to determine if giving employees more control over how to do their work leads to increased job satisfaction. One way to examine this possibility would be to conduct an animal study. Your dependent variable is the brain activity response to hearing infant cries. 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. Although there are many types of bias, two common types are selection bias and information bias. Quantitative variables are any variables where the data represent amounts (e.g. It represents the cause or reason for an outcome. A confounding variable, also called a confounder or confounding factor, is a third variable in a study examining a potential cause-and-effect relationship. A company that specializes in essential oils wants to examine the effects of lavender on sleep quality. For experimental data, you analyze your results by generating descriptive statistics and visualizing your findings. Types of data: Quantitative vs categorical variables, Parts of the experiment: Independent vs dependent variables, Frequently asked questions about variables. Learn more about our academic and editorial standards. The independent variable is the condition that you change in an experiment. We cite peer reviewed academic articles wherever possible and reference our sources at the end of our articles. by 2019;10(1):82-86. doi:10.4103/idoj.IDOJ_468_18. Performance & security by Cloudflare. 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. Any measurement of plant health and growth: in this case, plant height and wilting. 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. You want to find out how blood sugar levels are affected by drinking diet soda and regular soda, so you conduct an experiment. Before Definition and examples of dependent variable Independent variables are the ones we can freely manipulate, by plugging in any input value. 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. Its the outcome youre interested in measuring, and it depends on your independent variable. Revised on December 5, 2022. The mass of algae is the dependent variable. The value of a dependent variable depends on an independent variable, so a variable cannot be both independent and dependent at the same time. 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. Variables are given a special name that only applies to experimental investigations. For example, star ratings on product reviews are ordinal (1 to 5 stars), but the average star rating is quantitative. A variable is called dependent if a derivative of that variable occurs. There are two types of quantitative variables: discrete and continuous. J Health Care Chaplain. In these cases you may call the preceding variable (i.e., the rainfall) the predictor variable and the following variable (i.e. With Some people take vitamins every day. You want to compare brands of paper towels, to see which holds the most liquid. So, they use Photoshop to manipulate the same image of a female by altering the color of her hair: blonde, brunette, red, and brown. 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. Evidence-Based Complementary and Alternative Medicine, vol. https://www.thoughtco.com/independent-and-dependent-variable-examples-606828 (accessed March 4, 2023). The independent variables in a particular experiment all depend on the hypothesis and what the experimenters are investigating. If you determine the substance is necessary for proper nutrition, a follow-up experiment might determine how much of the chemical is needed. Then the crash experts rammed each car into a crash wall at the same speed. 2023 Dotdash Media, Inc. All rights reserved. You find some and conclude that gender identity influences brain responses to infant cries. Is the researcher trying to understand whether or how this variable affects another variable? Each participant sits in front of a computer screen and responds to questions on a survey. In statistical research, a variable is defined as an attribute of an object of study. Here the independent variable is the dose and the dependent variable is the frequency/intensity of symptoms . Women are more attracted to men without earrings than men with earrings. PMC Independent variable causes an effect on the dependent variable. Blazing Angels or Resident Evil? The researchers record how much time elapses from the moment they enter the room to the moment they leave. 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. Taylor, J. M., & Rowe, B. J. The dependent variable would be the amount of liquid absorbed by the paper towel. Based on your results, you note that the placebo and low-dose groups show little difference in blood pressure, while the high-dose group sees substantial improvements. Do tomatoes grow fastest under fluorescent, incandescent, or natural light? This doesn't really make sense (unless you can't sleep because you are worried you failed a test, but that would be a different experiment). 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. The key point here is that we have made it absolutely clear what we mean by the terms as they were studied and measured in our experiment. 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. In addition, the article links terminology about variables with the concept of levels of measurement in research.