In a well-designed experimental study , the independent variable is the only important difference between the experimental e. The dependent variable is the variable being tested and measured in an experiment, and is 'dependent' on the independent variable. An example of a dependent variable is depression symptoms, which depends on the independent variable type of therapy.
In an experiment, the researcher is looking for the possible effect on the dependent variable that might be caused by changing the independent variable. For example, we might change the type of information e. In this particular example the type of information is the independent variable because it changes and the amount of information remembered is the dependent variable because this is being measured.
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. 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.
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. Confounding variables lead to bias, or a factor that may cause an estimate to differ from the true population value.
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. Although there are many types of bias, two common types are selection bias and information bias.
Those who listened to Mozart daily Group A scored significantly higher on the reading test. In a study with a similar design as the previous example, researchers looked at the effects of nutrition on reading ability. In Group A, children ate at least three ounces of dark green vegetables every day for one month. In Group B, children were fed their regular diet. At the end of the month, the children took a reading comprehension test. Those who ate the green vegetables every day for one month Group A did not vary in their test scores when compared to Group B.
Dependent Variable:. Independent Variable:. Variables are important to understand because they are the basic units of the information studied and interpreted in research studies.
Researchers carefully analyze and interpret the value s of each variable to make sense of how things relate to each other in a descriptive study or what has happened in an experiment. Definition : Variables are characteristics studied in research that can take on different values e. Many children who live in the Bronx, a borough of New York City, are developing asthma.
In a descriptive study investigating this problem, parents whose children have asthma are asked about whether they smoke around their child, whether they live near a freeway, whether their child regularly sees a healthcare provider, their family income level and also if there is a history in their family of asthma.
It must be either the cause or the effect, not both! Yes, but including more than one of either type requires multiple research questions.
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. Each of these is its own dependent variable with its own research question. 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.
Each of these is a separate independent variable. To ensure the internal validity of an experiment , you should only change one independent variable at a time. Have a language expert improve your writing. Check your paper for plagiarism in 10 minutes. Do the check. Generate your APA citations for free! APA Citation Generator. Home Knowledge Base Methodology Independent and dependent variables. Independent and dependent variables Published on May 20, by Lauren Thomas.
The independent variable is the cause. Its value is independent of other variables in your study. The dependent variable is the effect. Its value d epends on changes in the independent variable.
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