Be careful with these, because confounding variables run a high risk of introducing a variety of. Sometimes the dependent variable is called the "responding 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. Amanda Tust is a fact-checker, researcher, and writer with a Master of Science in Journalism from Northwestern University's Medill School of Journalism. 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. 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. Careers. A confounding variable is related to both the supposed cause and the supposed effect of the study. This is a quasi-experimental design because theres no random assignment. Verywell Mind content is rigorously reviewed by a team of qualified and experienced fact checkers. Can I include more than one independent or dependent variable in a study? Scribbr. She has taught science courses at the high school, college, and graduate levels. About The Helpful Professor In this example, the color of the office is the independent variable. The x-axis is the independent variable, while the y-axis is the dependent variable. All articles are edited by a PhD level academic. This includes rankings (e.g. 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. What type of data does the variable contain? Definition and examples of dependent variable Independent variables are the ones we can freely manipulate, by plugging in any input value. What is the difference between discrete and continuous variables? 2.2: Concepts, Constructs, and Variables - Social Sci LibreTexts Nursing 360: Independent Variable VS Dependent Variable Click to reveal Select independent variables that you think will cause changes in another variable. 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. Participants aged between 16 30 will recall significantly more nouns from a list of twenty than participants aged between 55 70 is operationalized. They hire a sleep research lab to conduct the study. 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. By manipulating the level of an independent variable and observing corresponding changes in a dependent variable, scientists can gain an understanding of many phenomena. government site. So, they create three bridge molds that are identical in every way. Read our, Introduction to Psychology Research Methods, Internal Validity vs. What Are Independent and Dependent Variables? Your email address will not be published. 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. You find some and conclude that gender identity influences brain responses to infant cries. You want to compare brands of paper towels, to see which holds the most liquid. The dependent variable would be the amount of liquid absorbed by the paper towel. A variable that cant be directly measured, but that you represent via a proxy. 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. In z = 3x2 - 2y3, z is the dependent variable. 2018 Jan;9(1):12-21. doi: 10.1037/per0000254. If you have the variables in the wrong order, the sentence won't make sense. Glossary - United States National Library of Medicine Variables that are held constant throughout the experiment. Learn more about our academic and editorial standards. The only way to do that is to manipulate the independent variable and observe any changes in the dependent variable. Here are the definitions for independent and dependent variables, examples of each variable, and the explanation for how to graph them. by The dependent variable is the condition that you measure in an experiment. Rumrill, P. D., Jr. (2004). (2012). Retrieved from https://www.thoughtco.com/independent-and-dependent-variable-examples-606828. There are three types of categorical variables: binary, nominal, and ordinal variables. You want to know which brand of microwave popcorn pops the best. Pritha Bhandari. independent and dependent variable examples thoughtco, understanding co2 lasers, inferring from data home ubalt edu, independent variables and dependent . What is a dependent variable simple definition | Math Index Independent vs. Your email address will not be published. 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. height, weight, or age). National Library of Medicine Distinguishing between independent and dependent variables can be tricky when designing a complex study or reading an academic research paper. Is the researcher trying to understand whether or how this variable affects another variable? Does this variable get measured only after other variables are altered? Next, they test the strength of each bridge by placing progressively more weight on its center until the bridge collapses. Youll often use t tests or ANOVAs to analyze your data and answer your research questions. . 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 cause, and the dependent variable is the effect. You want to compare brands of paper towels, to see which holds the most liquid. People learn more when they study in a quiet versus noisy place. Ferguson, C. J. PMC 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. How should we measure stress? 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. 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. December 2, 2022. 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. Your independent variable is the treatment that you directly vary between groups. 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. Age is the independent variable. Linear regression is used to quantify the relationship between 1 independent (predictor) variables and a continuous dependent (outcome) variable. Independent variable causes an effect on the dependent variable. 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. The health of the rat (whether it lives and can reproduce) is the dependent variable. *Note that sometimes a variable can work as more than one type! An independent variable is the variable you manipulate, control, or vary in an experimental study to explore its effects. What Is a Dependent Variable? - Verywell Mind A variable that is made by combining multiple variables in an experiment. The first is that the researchers manipulate, or systematically vary, the level of the independent variable. 2. In this animal study, the independent variable would be car exhaust and the dependent variable would be amount of time to run a maze. In your research design, its important to identify potential confounding variables and plan how you will reduce their impact. Each of these is a separate independent variable. Is medical marijuana effective for pain reduction in people with chronic pain? 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. A correlational research design investigates relationships between variables without the researcher controlling or manipulating any of them. People in the pizza business know that the crust is key. 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 A company that specializes in essential oils wants to examine the effects of lavender on sleep quality. 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. The independent variable is hair color, and the dependent variable is pupil dilation. ____________________________________________________________. The independent variable in this sleep study is lavender, and the dependent variable is the total amount of time spent in deep sleep. 3. Its essential to know which is the cause the independent variable and which is the effect the dependent variable. Then the crash experts rammed each car into a crash wall at the same speed. The dependent variable (height) depends on the independent variable (age). Then, you select an appropriate statistical test to test your hypothesis. In statistical research, a variable is defined as an attribute of an object of study. FOIA 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. Variables are given a special name that only applies to experimental investigations. Clipboard, Search History, and several other advanced features are temporarily unavailable. Cloudflare Ray ID: 7a29bcd96f01c31d Helmenstine, Anne Marie, Ph.D. "What Are Independent and Dependent Variables?" 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. 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. Another way to put it is the dependent variable is the output value and the independent variable is the input value. In analytical health research there are generally two types of variables. Independent and Dependent Variable Examples, How to Tell the Independent and Dependent Variable Apart. J Exp Soc Psychol. How hungry you are would be the dependent variable. The dependent variable will always be the variable that is held constant. A large food company is considering entering the health and nutrition sector. Confounding variables lead to bias, or a factor that may cause an estimate to differ from the true population value. Epub 2016 Mar 24. 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. Accessibility A confounding variable, or confounder, affects the relationship between the independent and dependent variables. It is the main point of focus in the experiment whereby researchers are looking to find a cause to. Types of Variables in Research & Statistics | Examples. For example, in a plant growth study, the independent variables might be soil moisture (continuous) and type of fertilizer (categorical). 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. Independent and Dependent Variables: Differences & Examples Of course, they would prefer that consumers enter and exit quickly to increase sales volume and profit. _________________________________________________________, D.V. Keywords: 2. Categorical variables represent groupings of some kind. Other variations of an experiment might include having multiple levels of the independent variable. Based on your findings, you can estimate the degree to which your independent variable variation drives changes in your dependent variable. 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. The health of the rat (whether it lives and reproduces) is the dependent variable. So for y=x+3, when you input x=2, the output is y = 5. The article explains that the terms extraneous, nuisance, and confounding variables refer to any variable that can interfere with the ability to establish relationships between independent variables and dependent variables, and it describes ways to control for such confounds. In this study, the independent variable is the concrete mixture, and the dependent variable is the amount of weight at collapse. ThoughtCo, Aug. 27, 2020, thoughtco.com/independent-and-dependent-variable-examples-606828. The independent variable is the condition that you change in an experiment. [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. 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. Unauthorized use of these marks is strictly prohibited. I.V. 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. 88.99.24.175 Are you ready to take control of your mental health and relationship well-being? Studentsshould always cross-check any information on this site with their course teacher. In an experiment, you manipulate the independent variable and measure the outcome in the dependent variable. For the following hypotheses, name the IV and the DV. 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. Independent variables also have different levels. You vary the room temperature by making it cooler for half the participants, and warmer for the other half. At the end of the survey, the screen shows one of the photos of the female. The independent variable is the variable that is being manipulated, or the one that varies. The other half do not take the vitamins. Saul Mcleod, Ph.D., is a qualified psychology teacher with over 18 years experience of working in further and higher education. In experiments, you manipulate independent variables directly to see how they affect your dependent variable. 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. Variables that represent the outcome of the experiment. There are two main types of independent variables. Choosing a health behaviour theory or model for related research projects: a narrative review. Types of Variables and Commonly Used Statistical Designs These concepts should not be confused with predictor and outcome variables. To understand this concept, it's helpful to take a look at the independent variable in research examples. Seekprofessional input on your specific circumstances. In research, variables are any characteristics that can take on different values, such as height, age, temperature, or test scores. 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. National Library of Medicine You think rising sea temperatures might affect the amount of algae in the water. Each of these types of variables can be broken down into further types. 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. If you are designing an experiment, here are a few tips for choosing an independent variable (or variables): It is also important to be aware that there may be other variables that might influence the results of an experiment. This website is using a security service to protect itself from online attacks. One common way of assessing cognitive performance in laboratory rats is by measuring the amount of time it takes to run a maze successfully. The independent variable is the color of the room, and the dependent variable is the amount of time spent in the room eating. The amount of skull damage of dummies in cars with airbags was then compared with those without airbags. The independent variable and dependent variable are used in a very specific type of scientific study called the experiment. An official website of the United States government. But before we begin, we need to briefly review the difference between independent and dependent variables. Although there are many variations of the experiment, generally speaking, it involves either the presence or absence of the independent variable and the observation of what happens to the dependent variable. Although two variables may be correlated, this does not imply that there is a causal relationship between them. 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). J Res Nurs. The researchers identified 120 patients with relatively similar types of cancerous tumors in both size and stage of progression. Relate post: Effect Sizes in Statistics Each athlete will run on a treadmill for one hour while their heart rate is tracked. After three months, we measure the stress levels of each person and compare the groups. 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 term causation is vitally important. In these cases you may call the preceding variable (i.e., the rainfall) the predictor variable and the following variable (i.e. In an experiment, one group of students attends an after-school tutoring session twice a week while another group of students does not receive this additional assistance. 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 independent variables in a particular experiment all depend on the hypothesis and what the experimenters are investigating. ThoughtCo. Categorical variables are any variables where the data represent groups. The independent variable is Mozart, and the dependent variable is exam scores. Dependent and Independent variables Example of Denominator In p = 4q, p is the dependent variable, because its value depends on the value of q. The presence/absence of the chemical is the independent variable. HHS Vulnerability Disclosure, Help 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. ANOVA tells you if the dependent variable changes according to the level of the independent variable. In other words, whether changes in an independent variable cause a change in a dependent variable. The company wants to know which version is the strongest. Boston, MA: Cengage Learning; 2017. Dr. Helmenstine holds a Ph.D. in biomedical sciences and is a science writer, educator, and consultant. You suspect the amount of television a person watches is related to their age. Taylor, J. M., & Rowe, B. J. 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. Dependent variable Definition and Examples. Blazing Angels or Resident Evil? Your dependent variable is math test scores. 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. Bhandari, P. Below is an example of using independent and dependent variables in an ecological study: A government agency handles environmental care in a city. Is this variable dependent on another variable in the study? The independent variable in this example is the type of therapy. Independent Variable Definition and Examples - ThoughtCo.com is the Other 5th grade classrooms will not listen to any music during their lessons and exams. They randomly select 1,000 people that are relatively similar in terms of their physical health. Example: How long you sleep (independent variable) affects your test score (dependent variable). You can also predict how much your dependent variable will change as a result of variation in the independent variable. Dependent Variables | Definition & Examples. You use this measurement data to check whether and to what extent your independent variable influences the dependent variable by conducting statistical analyses. The .gov means its official. For example, gender identity, ethnicity, race, income, and education are all important subject variables that social researchers treat as independent variables. In addition, the article links terminology about variables with the concept of levels of measurement in research. If they can back up that claim with hard scientific data, that would be great for sales. FOIA HHS Vulnerability Disclosure, NLM Support Center For the following hypotheses, name the IV and the DV and operationalize both variables. The independent variable is the variable the experimenter manipulates or changes and is assumed to directly affect the dependent variable. 4. 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. 15 Independent and Dependent Variable Examples (2023) - Helpful Professor In this highly unrealistic study, the independent variable is vitamins, and the dependent variable is health, as measured by blood pressure and cholesterol levels. The other half takes the same amount of something that looks the same but actually does nothing to the body. At the end of one year, the health of all participants is assessed, using blood pressure and cholesterol level as the key measurements. The three plant health variables could be combined into a single plant-health score to make it easier to present your findings. Quantitative variables are any variables where the data represent amounts (e.g. Note that any research methods that use non-random assignment are at risk for research biases like selection bias and sampling bias. 2011, Article ID 960583. https://doi.org/10.1155/2011/960583. Unable to load your collection due to an error, Unable to load your delegates due to an error. A business wants to determine if giving employees more control over how to do their work leads to increased job satisfaction. In this example, the independent variable is Gatorade, and the dependent variable is heart rate. In this case, participation in after-school math tutoring is the independent variable. A lot of those studies used an experimental design that involved males of various ages randomly assigned to play a graphic or non-graphic video game. An ordinal variable can also be used as a quantitative variable if the scale is numeric and doesnt need to be kept as discrete integers. Educators are interested in whether participating in after-school math tutoring can increase scores on standardized math exams. Non-manipulation quantitative designs. SPICE (Setting, Perspective, Intervention/phenomenon of Interest, Comparison, Evaluation) Appropriate for : evaluating the outcomes of a service, project, or intervention Its the outcome youre interested in measuring, and it depends on your independent variable. Your dependent variable is the brain activity response to hearing infant cries. Rebecca Bevans. 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). Your independent variable is a subject variable, namely the gender identity of the participants. Independent variable causes an effect on the dependent variable. A hospital is investigating the effectiveness of a new type of chemotherapy on cancer. Time of day has a significant effect on alertness. Although there are many types of bias, two common types are selection bias and information bias. 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. A follow-up experiment might determine how much of the chemical is needed. This makes sense, but: Example: Your test score affects how long you sleep. If you have the variables in the wrong order, the sentence won't make sense. ___________________________________________________________. The independent variable was the airbag and the dependent variable was the amount of skull damage. MeSH An example of a dependent variable is how tall you are at different ages. An example of a dependent variable is depression symptoms, which depends on the independent variable (type of therapy). The company approaches several gyms near its headquarters. A chemicals company has developed three different versions of their concrete mix. 1. He has trained kindergarten teachers in 8 countries and helped businessmen and women open baby centers and kindergartens in 3 countries. No. When you collect quantitative data, the numbers you record represent real amounts that can be added, subtracted, divided, etc. 2016 Sep;66:29-38. doi: 10.1016/j.jesp.2015.09.012. There can be all different types of independent variables. Its not possible to randomly assign these to participants, since these are characteristics of already existing groups. 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. Revised on December 5, 2022. Dependent & independent variables. 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.
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