Question

which of the following best defines test variable (independent variable)?
the variable that is purposely changed in an experiment.
the variable that responds to the outcome variable.
the variable that stays the same in an experiment.
the variable that is measured in an experiment.

Explanation:

An independent variable (test variable) is a variable that is manipulated or changed in an experiment to observe its effect on the dependent variable. The other options describe dependent variable (responds to outcome variable), constant (stays the same), and dependent variable (measured) respectively.

Answer:

The variable that is purposely changed in an experiment.