Which Factor in an Experiment Can Be Manipulated

Question

Which factor in an experiment can be manipulated?
A) bias
B) control
C) placebo
D) variable

Accepted Answer

The variable is the factor in an experiment that can be manipulated or changed in order to study its effect on the outcome. The other options, bias, control, and placebo, are all related to factors that can impact the validity of an experiment, but they cannot be manipulated in the same way as the variable.