Dependent variable
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In experimental design, a dependent variable (also known as response variable or regressand) is a factor whose values in different treatment conditions are compared. That is, the experimenter is interested in determining if the value of the dependent variable varies when the values of another variable – the independent variable – are varied, and by how much. In simple terms, the independent variable is said to cause an apparent change in, or simply affect, the dependent variable. In analysis, researchers usually want to explain why the dependent variable has a given value. In research, the values of a dependent variable in different settings are usually compared.
Other terms for the dependent variable are y-variable, outcome variable, and response variable.
[edit] Scientific usage
When observing a physical process, the dependent variable is measured by the scientist, in order to determine the effect of the independent variable. Often the independent variable is a physical quality measured on a system that changes over time, possibly as a result of adjusting another physical parameter (the independent variable). To visualize the effect of the independent variable on the dependent variable, a line chart is commonly used. This effect is also called the “response” or the “relation.” The dependent variable is the response to the independent variable.
[edit] Mathematics usage
In the graphing of data, the dependent variable goes on the y-axis (see Cartesian coordinates).
In mathematics, the dependent variable is usually represented as a function of the independent variables. For example, in the explicit equation y = 4x2 + x, the dependent variable y can be written as a function of the independent variable x, as y(x). When represented this way, it is more common to refer to the dependent variable as a function, and the independent variable as just a variable.
[edit] Examples
In a study of how different dosages of a drug are related to the severity of symptoms of a disease, a measure of the severity of the symptoms of the disease is a dependent variable and the administration of the drug in specified doses is the independent variable. A researcher will compare the different values of the dependent variable (severity of the symptoms) and attempt to draw a conclusion.
In measuring the amount of colour removed from beetroot samples at different temperatures, the dependant variable would be the amount of pigment removed, because it is depending on the temperature (which is the independant variable).
