In
experimental design, an
independent variable is a
variable used to define treatment groups. For example, in a study of how different dosages of a drug are related to the severity of symptoms of a disease, the specific doses selected by the experimenters for investigation are the independent variable, while a measure of the severity of the symptoms of the disease is a
dependent variable.
More generally, the independent variable is the thing that someone actively controls/changes; while the dependent variable is the thing that changes as a result.
When graphing a set of collected data, the independent variable is graphed on the x-axis.
Category:Experimental design