Youll often use t tests or ANOVAs to analyze your data and answer your research questions. If you have the variables in the wrong order, the sentence won't make sense. 2. What are independent and dependent variables? Read our, Introduction to Psychology Research Methods, Internal Validity vs. 2023 Simply Psychology - Study Guides for Psychology Students. A variable is called dependent if a derivative of that variable occurs. The independent variable is the teaching method, and the dependent variable is performance on the critical thinking test. Does practicing meditation reduce stress? In an experiment, you manipulate the independent variable and measure the outcome in the dependent variable. Careers. To keep track of your salt-tolerance experiment, you make a data sheet where you record information about the variables in the experiment, like salt addition and plant health. This helps you to have confidence that your dependent variable results come solely from the independent variable manipulation. To understand this concept, it's helpful to take a look at the independent variable in research examples. Sensors on the crash dummy skulls allowed for a scientific analysis of how much damage a human skull would incur. 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. Epub 2016 Mar 24. A chemicals company has developed three different versions of their concrete mix. Dave Cornell (PhD) and Peer Reviewed by Chris Drew (PhD), Definition of Independent and Dependent Variables, Examples of Independent and Dependent Variables, 1. 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. 1. Independent and Dependent Variable Examples The presence/absence of the chemical is the independent variable. 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. Revised on You measure the math skills of all participants using a standardized test and check whether they differ based on room temperature. Although two variables may be correlated, this does not imply that there is a causal relationship between them. The relationship makes sense and identifies the independent variable as phone use and the dependent variable as sleep quality. It must be either the cause or the effect, not both! Their muscle mass is measured, and only those with a lower level are selected for the study, leaving a total of 80 study participants. But before we begin, we need to briefly review the difference between independent and dependent variables. 2011, Article ID 960583. https://doi.org/10.1155/2011/960583. Kaliyadan F, Kulkarni V. Types of variables, descriptive statistics, and sample size. 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). A variable that cant be directly measured, but that you represent via a proxy. There are three types of categorical variables: binary, nominal, and ordinal variables. Can graphic video games be a force for good? Click to reveal A sports medicine researcher has been hired by Gatorade to test the effects of its sports drink on athletic performance. The independent variable in this sleep study is lavender, and the dependent variable is the total amount of time spent in deep sleep. Can graphic video games be a force for good? 4. This website is using a security service to protect itself from online attacks. 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. https://www.thoughtco.com/independent-and-dependent-variable-examples-606828 (accessed March 4, 2023). In this animal study, the independent variable would be car exhaust and the dependent variable would be amount of time to run a maze. The researchers at the lab have their usual test volunteers sleep in individual rooms every night for one week. Bookshelf Weiten, W. Psychology: Themes and Variations, 10th ed. You want to know which brand of fertilizer is best for your plants. Bethesda, MD 20894, Web Policies Below are the key differences when looking at an independent variable vs. dependent variable. They then indicate how much they liked it by pressing one of 5 buttons: didnt like at all, liked, somewhat liked, liked very much, loved it. Brain morphology, harm avoidance, and the severity of excessive internet use. Time of day has a significant effect on alertness. This can happen when another variable is closely related to a variable you are interested in, but you havent controlled it in your experiment. sharing sensitive information, make sure youre on a federal Researchers want to determine if a new type of treatment will lead to a reduction in anxiety for patients living with social phobia. The dependent variable is the volume of liquid absorbed by the paper towel. For example, in an experiment looking at the effects of studying on test scores, studying would be the independent variable. The independent variables in a particular experiment all depend on the hypothesis and what the experimenters are investigating. What is the difference between discrete and continuous variables? In this case, participation in after-school math tutoring is the independent variable. The dependent variable is the variable that is being measured or tested in an experiment. Confounding variables lead to bias, or a factor that may cause an estimate to differ from the true population value. 3. Determining cause and effect is one of the most important parts of scientific research. It is called independent because its value does not depend on and is not affected by the state of any other variable in the experiment. 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. For example, gender identity, ethnicity, race, income, and education are all important subject variables that social researchers treat as independent variables. If we didnt do this, then it would be very difficult (if not impossible) to compare the findings of different studies to the same behavior. (2022, December 02). Variables that represent the outcome of the experiment. Next, they test the strength of each bridge by placing progressively more weight on its center until the bridge collapses. Afterward, their level of aggression was measured via a wide range of methods, including direct observations of their behavior, their actions when given the opportunity to be aggressive, or a variety of other measures. Subscribe now and start your journey towards a happier, healthier you. Your independent variable is the treatment that you directly vary between groups. The researchers then compare the scores of the exams between the two groups of classrooms. About The Helpful Professor (2010). A variable that hides the true effect of another variable in your experiment. This can provide very valuable information when studying just about any subject. So, they create three bridge molds that are identical in every way. _________________________________________________________, D.V. Yes, but including more than one of either type requires multiple research questions. from https://www.scribbr.com/methodology/types-of-variables/, Types of Variables in Research & Statistics | Examples, , the terms dependent and independent dont apply, because you are not trying to establish a cause and effect relationship (. It's the outcome you're interested in measuring, and it 'depends' on your independent variable. Linear regression is used to quantify the relationship between 1 independent (predictor) variables and a continuous dependent (outcome) variable. For example, if you're studying whether a change in temperature affects productivity, the independent variable would be the room temperature, and the dependent . Sometimes you may hear this variable called the "controlled variable" because it is the one that is changed. The brand of popcorn is the independent variable. It is the main point of focus in the experiment whereby researchers are looking to find a cause to. Measures of central tendency in chaplaincy, health care, and related research. Plausible alternative explanations are other factors that may cause the dependent variable under observation.[4]. December 2, 2022. 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. In statistics, dependent variables are also called: The dependent variable is what you record after youve manipulated the independent variable. If you want to know whether caffeine affects your appetite, the presence/absence or amount of caffeine is the independent variable. ), 22(3), 255260. Operational variables (or operationalizing definitions) refer to how you will define and measure a specific variable as it is used in your study. Are you ready to take control of your mental health and relationship well-being? The conditions of each room are all exactly the same, except that half of the rooms have lavender released into the rooms and half do not. The dependent variable will always be the variable that is held constant. Rebecca Bevans. Independent variables are the variables that the experimenter changes to test their dependent variable. A variable that is made by combining multiple variables in an experiment. The only way to do that is to manipulate the independent variable and observe any changes in the dependent variable. 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. Your independent variable is a subject variable, namely the gender identity of the participants. 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. What is the effect of intermittent fasting on blood sugar levels? A dependent variable is the variable that changes as a result of the independent variable manipulation. These terms are especially used in statistics, where you estimate the extent to which an independent variable change can explain or predict changes in the dependent variable. One is called the dependent variable, and the other is the independent variable. How to identify independent variables vs. dependent variables. 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. Example: How long you sleep (independent variable) affects your test score (dependent variable). What part of the experiment does the variable represent? For example: In a study of how different doses of a drug affect the severity of symptoms, a researcher could compare the frequency and intensity of symptoms when different doses are administered. You vary the room temperature by making it cooler for half the participants, and warmer for the other half. Reviewers ensure all content reflects expert academic consensus and is backed up with reference to academic studies. The brand of fertilizer is the independent variable. 2008;14(1):3-19. doi: 10.1080/08854720802053796. Next, they randomly select shoppers on Saturdays and Sundays to eat for free in one of the three rooms. For example, allocating participants to drug or placebo conditions (independent variable) to measure any changes in the intensity of their anxiety (dependent variable). Researchers often manipulate or measure independent and dependent variables in studies to test cause-and-effect relationships. Example: What are the experiences and perspectives of undergraduate nursing students in clinical placements within prison healthcare settings? Any measurement of plant health and growth: in this case, plant height and wilting. You use this measurement data to check whether and to what extent your independent variable influences the dependent variable by conducting statistical analyses. One is called the dependent variable, and the other is the independent variable. Relate post: Effect Sizes in Statistics 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. To ensure the internal validity of an experiment, you should only change one independent variable at a time. The independent variable is the cause, and the dependent variable is the effect. The amount of skull damage of dummies in cars with airbags was then compared with those without airbags. 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. In this experiment, we have one independent and three dependent variables. It's what changes as a result of the changes to the independent variable. ThoughtCo, Aug. 27, 2020, thoughtco.com/independent-and-dependent-variable-examples-606828. This example sheet is color-coded according to the type of variable: nominal, continuous, ordinal, and binary. Published on You want to compare brands of paper towels, to see which holds the most liquid. You can email the site owner to let them know you were blocked. 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. Verywell Mind's content is for informational and educational purposes only. ____________________________________________________________, I.V. 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. Accessibility Although there are many types of bias, two common types are selection bias and information bias. Does this variable get measured only after other variables are altered? What Are Independent and Dependent Variables? The independent variable in your experiment would be the brand of paper towel. The researchers record how much time elapses from the moment they enter the room to the moment they leave. If you want to know whether caffeine affects your appetite, the presence/absence of a given amount of caffeine would be the independent variable. Some people take vitamins every day. Verywell Mind content is rigorously reviewed by a team of qualified and experienced fact checkers. Educators are interested in whether participating in after-school math tutoring can increase scores on standardized math exams. If you write out the variables in a sentence that shows cause and effect, the independent variable causes the effect on the dependent variable. By varying the level of the independent variable and observing associated changes in the dependent variable, a researcher can conclude whether the independent variable affects the dependent variable or not. Work (Reading, Mass. Next, they randomly select university males to enter their testing facilities. 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. You have three independent variable levels, and each group gets a different level of treatment. (2012). . Example: Independent variable levels You are studying the impact of a new medication on the blood pressure of patients with hypertension. A confounding variable is related to both the supposed cause and the supposed effect of the study. The researchers identified 120 patients with relatively similar types of cancerous tumors in both size and stage of progression. In research, variables are any characteristics that can take on different values, such as height, age, temperature, or test scores. You think rising sea temperatures might affect the amount of algae in the water. In this study, the independent variable is the concrete mixture, and the dependent variable is the amount of weight at collapse. Taylor, J. M., & Rowe, B. J. Fact checkers review articles for factual accuracy, relevance, and timeliness. Bias is a systematic error in study design, subject recruitment, data collection, or analysis that results in a mistaken estimate of the true population parameter.[2]. The health of the rat (whether it lives and can reproduce) is the dependent Stressful experiences significantly increase the likelihood of headaches. 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 temperature and light in the room the plants are kept in, and the volume of water given to each plant. Verywell Mind uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Examples of Independent and Dependent Variables in Experiments The company has prepared three versions of their crust that vary in crunchiness, they are: a little crunchy, very crunchy, and super crunchy. Federal government websites often end in .gov or .mil. This article begins by defining the term variable and the terms independent variable and dependent variable, providing examples of each. 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. 2. At the outset of an experiment, it is important for researchers to operationally define the independent variable. The independent variable is the supplement, and the dependent variable is muscle mass. Since then, there have been hundreds of studies conducted by psychologists and other researchers. coin flips). Bevans, R. For example, age, sex, current smoking, LDL cholesterol level, and blood pressure are independent variables because their values (e.g., greater age, positive for current smoking, and higher LDL cholesterol level) influence the risk of myocardial infarction. Choosing which variables to measure is central to good experimental design. HHS Vulnerability Disclosure, Help Gatorade and Improved Athletic Performance, 15. Is this variable dependent on another variable in the study? Your dependent variable is the brain activity response to hearing infant cries.