Then, you select an appropriate statistical test to test your hypothesis. Pritha Bhandari. Below are the key differences when looking at an independent variable vs. dependent variable. The independent variable in this sleep study is lavender, and the dependent variable is the total amount of time spent in deep sleep. In other cases, researchers might find that changes in the independent variables have no effect on the variables that are being measured. Click to reveal However, there might be cases where one variable clearly precedes the other (for example, rainfall leads to mud, rather than the other way around). It can be difficult to separate the true effect of the independent variable from the effect of the confounding variable. 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. Design approaches to experimental mediation. An independent variable is the variable you manipulate or vary in an experimental study to explore its effects. 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. Independent vs. A dependent variable is the variable that changes as a result of the independent variable manipulation. Its the outcome youre interested in measuring, and it depends on your independent variable. When you collect quantitative data, the numbers you record represent real amounts that can be added, subtracted, divided, etc. An example of a dependent variable is how tall you are at different ages. One room is painted mostly white with red trim and seats; one room is painted mostly white with blue trim and seats; and one room is painted mostly white with off-white trim and seats. Dr. Drew has published over 20 academic articles in scholarly journals. A Dependent variable is what happens as a result of the independent variable. Nominal and categorical variables describe samples in groups based on counts that fall within each category, have no quantitative relationships, and cannot be ranked. The brand of fertilizer is the independent variable. 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]. To determine the effect that traffic patterns have on the air in a city, employees at the agency perform a study that assesses car usage and air quality in cities around the country. In an experiment you would control these potential confounders by holding them constant. https://doi.org/10.1080/08854726.2014.959374, https://doi.org/10.1080/10790195.2012.10850354. Dependent and Independent variables Example of Denominator In p = 4q, p is the dependent variable, because its value depends on the value of q. In general, experiments have these three types of variables: independent, dependent, and controlled. After many claims that listening to Mozart will make you smarter, a group of education specialists decides to put it to the test. Here are the definitions for independent and dependent variables, examples of each variable, and the explanation for how to graph them. Disclaimer. Be careful with these, because confounding variables run a high risk of introducing a variety of. You vary the room temperature by making it cooler for half the participants, and warmer for the other half. 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. Random assignment helps you control participant characteristics, so that they dont affect your experimental results. A change in the independent variable directly causes a change in the dependent . Categorical variables are any variables where the data represent 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. A variable that hides the true effect of another variable in your experiment. 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. 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. Subject variables are characteristics that vary across participants, and they cant be manipulated by researchers. With External Validity in Research, Forming a Good Hypothesis for Scientific Research, Scientific Method Steps in Psychology Research, Psychology Research Jargon You Should Know, The Definition of Random Assignment According to Psychology, How the Experimental Method Works in Psychology, How Social Psychologists Conduct Their Research, Experimental Group in Psychology Experiments, Types of Variables in Psychology Research, How to Write an APA Method Section of a Research Paper, Wait List Control Groups in Psychology Experiments, Daily Tips for a Healthy Mind to Your Inbox, Types of variables, descriptive statistics, and sample size. One is called the dependent variable, and the other is the independent variable. Lack of sleep significantly affects learning in 10-year-old boys. An operational definition describes exactly what the independent variable is and how it is measured. The dependent variable will always be the variable that is held constant. In other words, whether changes in an independent variable cause a change in a dependent variable. The https:// ensures that you are connecting to the The researchers at the lab have their usual test volunteers sleep in individual rooms every night for one week. Your email address will not be published. Researchers want to determine if a new type of treatment will lead to a reduction in anxiety for patients living with social phobia. Salt tolerance in plants cannot be measured directly, but can be inferred from measurements of plant health in our salt-addition experiment. A correlation reflects the strength and/or direction of the relationship between two (or more) variables. Learn more about our academic and editorial standards. Verywell Mind content is rigorously reviewed by a team of qualified and experienced fact checkers. 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. Each version contains a different blend of specially developed chemicals. 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. As an Amazon Associate I earn from qualifying purchases. Educators are interested in whether participating in after-school math tutoring can increase scores on standardized math exams. confounds; dependent variable; independent variable; levels of measurement; mediation; moderation; risk factors. These variables are created when you analyze data, not when you measure it. The site is secure. Is the variable manipulated, controlled, or used as a subject grouping method by the researcher? An official website of the United States government. For example, star ratings on product reviews are ordinal (1 to 5 stars), but the average star rating is quantitative. The dependent variable is the variable being tested and measured in an experiment and is dependent on the independent variable. 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. coin flips). The company has prepared three versions of their crust that vary in crunchiness, they are: a little crunchy, very crunchy, and super crunchy. The dependent variable (height) depends on the independent variable (age). You have three independent variable levels, and each group gets a different level of treatment. 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. Pot size and soil type might affect plant survival as much or more than salt additions. You can email the site owner to let them know you were blocked. A large multinational cosmetics company wants to know if the color of a womans hair affects the level of perceived attractiveness in males. 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. In a representative example: Several crash cars were outfitted with an airbag, and an equal number were not. If you have the variables in the wrong order, the sentence won't make sense. Does this variable come before the other variable in time? 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. The researchers believe that larger dilation indicates greater perceived attractiveness. 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. In addition, the scientists randomly assign half of the participants to take a set of vitamins, supplied by the researchers every day for 1 year. Applying causal mediation analysis to personality disorder research. Each group receives chemotherapy treatment three times a week for two months, except for the no-treatment group. In this experiment, we have one independent and three dependent variables. _________________________________________________________, D.V. The dependent variable (sometimes known as the responding variable) is what is being studied and measured in the experiment. In this case, we must state what we mean by the terms media violence and aggression as we will study them. A group of health scientists decides to conduct a study to determine if taking vitamins improves health. An independent variable is defines as the variable that is changed or controlled in a scientific experiment. The dependent variable is the volume of liquid absorbed by the paper towel. To gather information about plant responses over time, you can fill out the same data sheet every few days until the end of the experiment. The amount of skull damage of dummies in cars with airbags was then compared with those without airbags. 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 (. Retrieved from https://www.thoughtco.com/independent-and-dependent-variable-examples-606828. The company approaches several gyms near its headquarters. An example of a dependent variable is depression symptoms, which depend on the independent variable (type of therapy). Unauthorized use of these marks is strictly prohibited. Generally, the independent variable goes on the x-axis (horizontal) and the dependent variable on the y-axis (vertical). After a certain period of time, perhaps several months, the effects on cognitive performance could be measured. All articles are edited by a PhD level academic. The brand of popcorn is the independent variable. by J Exp Soc Psychol. and transmitted securely. 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. There are three types of categorical variables: binary, nominal, and ordinal variables. In statistics, dependent variables are also called: The dependent variable is what you record after youve manipulated the independent variable. 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. A well-known fast-food corporation wants to know if the color of the interior of their restaurants will affect how fast people eat. It is sometimes called the 'predictor' or 'treatment' variable. Its called independent because its not influenced by any other variables in the study. Dependent Variables | Definition & Examples. While the study participants are sleeping, their heart rates and amount of time spent in deep sleep are recorded with high-tech equipment. The key word here is similar.. A variable is called dependent if a derivative of that variable occurs. All crash cars were of the same make, year, and model. You suspect the amount of television a person watches is related to their age. Federal government websites often end in .gov or .mil. In this case, participation in after-school math tutoring is the independent variable. So, they rent space in a large shopping mall and create three different simulated restaurant interiors of different colors. [8] Examples of these variables include: By contrast, the independent variable is the potential answer as to what is causing the change in the dependent variable. Bethesda, MD 20894, Web Policies The three plant health variables could be combined into a single plant-health score to make it easier to present your findings. Clipboard, Search History, and several other advanced features are temporarily unavailable. Your independent variable is the temperature of the room. In this natural experiment, a community living near higher concentrations of car exhaust may also live near factories that pollute or have higher rates of smoking. Participants aged between 16 30 will recall significantly more nouns from a list of twenty than participants aged between 55 70 is operationalized. 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. Next, they test the strength of each bridge by placing progressively more weight on its center until the bridge collapses. In these experimental studies, the independent variable was graphic video games, and the dependent variable was observed level of aggression. This article begins by defining the term variable and the terms independent variable and dependent variable, providing examples of each. 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. Variables that represent the outcome of the experiment. Ferguson, C. J. To ensure the internal validity of an experiment, you should only change one independent variable at a time. Kendra Cherry, MS, is an author and educational consultant focused on helping students learn about psychology. , 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 presence/absence of the chemical is the independent variable. The health of the plants (height, amount and size of flowers and fruit, color) is the dependent variable. In your research design, its important to identify potential confounding variables and plan how you will reduce their impact. If you are having trouble identifying the independent variables of an experiment, there are some questions that may help: Researchers are interested in investigating the effects of the independent variable on other variables, which are known as dependent variables (DV). Sometimes the dependent variable is called the "responding variable.". Statistical models will estimate effect sizes for the independent variables. by Indian Dermatol Online J. Chaplaincy research: its value, its quality, and its future. The independent variable in this example is the type of therapy. In experiments, you manipulate independent variables directly to see how they affect your dependent variable. Your email address will not be published. What is the difference between discrete and continuous variables? Definition and examples of dependent variable Independent variables are the ones we can freely manipulate, by plugging in any input value. There are several actions that could trigger this block including submitting a certain word or phrase, a SQL command or malformed data. National Library of Medicine Does this variable get measured only after other variables are altered? 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. At the end of three months, the muscle mass of all participants is measured. February 3, 2022 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. 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). The dependent variable would be the amount of liquid absorbed by the paper towel. They already have a pool of consumers that fit their customer profile and they often use them for testing. Number of different tree species in a forest, Rating scale responses in a survey, such as. 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. Its essential to know which is the cause the independent variable and which is the effect the dependent variable. But before we begin, we need to briefly review the difference between independent and dependent variables. finishing places in a race), classifications (e.g. Quantitative variables are any variables where the data represent amounts (e.g. The amount of salt added to each plants water. Is the variable something that cannot be changed but that is not dependent on other variables in the experiment? The independent variable was the airbag and the dependent variable was the amount of skull damage. https://www.thoughtco.com/independent-and-dependent-variable-examples-606828 (accessed March 4, 2023). Please include what you were doing when this page came up and the Cloudflare Ray ID found at the bottom of this page. Of course, you could also measure the number of unpopped kernels instead. 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. 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. Groups with no rank or order between them. Independent, dependent, and other variables in healthcare and chaplaincy research. Example: Independent variable levels You are studying the impact of a new medication on the blood pressure of patients with hypertension. The other half takes the same amount of something that looks the same but actually does nothing to the body. Our website is not intended to be a substitute for professional medical advice, diagnosis, or treatment. You want to find out how blood sugar levels are affected by drinking diet soda and regular soda, so you conduct an experiment. You have three independent variable levels, and each group gets a different level of treatment. A confounding variable is related to both the supposed cause and the supposed effect of the study. Revised on December 5, 2022. ____________________________________________________________. If they can back up that claim with hard scientific data, that would be great for sales. Other types of variables have interchangeable terms. In an experiment, one group of workers is given a great deal of input in how they perform their work, while the other group is not. 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). 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. Youll often use t tests or ANOVAs to analyze your data and answer your research questions. The researchers record how much time elapses from the moment they enter the room to the moment they leave. 1 Solve word questions too BSc (Hons) Psychology, MRes, PhD, University of Manchester. Evidence-Based Complementary and Alternative Medicine, vol. It represents the cause or reason for an outcome. But there are many other ways of describing variables that help with interpreting your results. 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. ), 22(3), 255260. So, first, they go to a nearby school in a middle-class neighborhood. 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. A dependent variable is the variable that changes as a result of the independent variable manipulation. Personal Disord. It's the outcome you're interested in measuring, and it 'depends' on your independent variable. 8600 Rockville Pike In analytical health research there are generally two types of variables. J Health Care Chaplain. So, the researcher goes to a nearby university and randomly selects both male and female athletes from several sports: track and field, volleyball, basketball, and football. Non-manipulation quantitative designs. The researchers identified 120 patients with relatively similar types of cancerous tumors in both size and stage of progression. 2019;10(1):82-86. doi:10.4103/idoj.IDOJ_468_18. 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 presence/absence of the chemical is the independent variable. If you want to know whether caffeine affects your appetite, the presence/absence of a given amount of caffeine would be the independent variable. It is the main point of focus in the experiment whereby researchers are looking to find a cause to. This makes sense, but: Example: Your test score affects how long you sleep. The other half do not take the vitamins. It's what changes as a result of the changes to the independent variable. The independent variable is the variable that is being manipulated, or the one that varies. There is a standard method for graphing the independent and dependent variable. Bevans, R. The independent variable is Mozart, and the dependent variable is exam scores. For example, in an experiment about the effect of nutrients on crop growth: Defining your variables, and deciding how you will manipulate and measure them, is an important part of experimental design. Before rolling out a new type of crust, the company decides to conduct some research on consumer preferences. Would you like email updates of new search results? (2012). The independent variable is usually applied at different levels to see how the outcomes differ. Read our, Introduction to Psychology Research Methods, Internal Validity vs. 1. The researchers then compare the scores of the exams between the two groups of classrooms. In this highly unrealistic study, the independent variable is vitamins, and the dependent variable is health, as measured by blood pressure and cholesterol levels. In this example, the color of the office is the independent variable. 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. It would also be possible to examine the physical effects of car exhaust on the brain by conducting an autopsy. In another example, the hypothesis Young participants will have significantly better memories than older participants is not operationalized. After collecting data, you check for statistically significant differences between the groups. Well, there are a lot of ways. 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. Next, they randomly select university males to enter their testing facilities. Kaliyadan F, Kulkarni V. Types of variables, descriptive statistics, and sample size. 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. Researchers often manipulate or measure independent and dependent variables in studies to test cause-and-effect relationships. You think rising sea temperatures might affect the amount of algae in the water. Please enable it to take advantage of the complete set of features! 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, say, y = x+3, then the value y can have depends on what the value of x is. This article was peer-reviewed and edited by Chris Drew (PhD). 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. No. In other cases, multiple levels of the IV may be used to look at the range of effects that the variable may have. This example sheet is color-coded according to the type of variable: nominal, continuous, ordinal, and binary.