Which term describes the variable that the researcher actively changes to observe effects?

• A. Independent variable
• B. Dependent variable
• C. Covariate
• D. Moderator

Answer: (A)

In an experiment, you deliberately manipulate a variable to see what effect it has on another variable. The one you actively change is the independent variable. It’s the input or cause you set up in the study—what you control to observe outcomes.

The variable you measure in response is the dependent variable—the outcome you assess after changing the independent variable.

A covariate is a variable you account for in analysis because it could influence the outcome, but you don’t manipulate it as a primary factor. A moderator is a variable that changes the strength or direction of the relationship between the independent and dependent variables (for example, the effect of study time on test scores might be stronger in one age group than another).

So, the term that describes the variable you actively change to observe effects is the independent variable.