Types of Variables

Explanatory & Response Variables

The main focus of an experiment are the two variables called the explanatory variable and the response variable. You may have also heard these variables called the independent and dependent variables in past math or psychology classes. However, in statistics courses we don't usually those terms because the independent variable doesn't necessarily have to be independent. 

Here are the definitions of these variables. We will go into more examples later.

Explanatory Variable: also known as the independent variable; This is the variable we are experimenting with to see what effect it has on another variable. The explanatory variable is something we have and can apply to a treatment group. 

Response Variable: also known as the dependent variable; This is the variable that is focus of our experiment. We observe how the response variable is affected by the explanatory variable. 

The explanatory variable explains the responses of the response variable.


Let's go through a few examples so you can get the hang of distinguishing these two types of variables.