Question

an independent variable is a. directly changed by the experimenter. b. manipulated by changes to the dependent variable. c. a variable that is kept constant. d. a variable that is used as a control. please select the best answer from the choices provided a b c d

Explanation:

An independent variable is the variable that the experimenter manipulates or changes directly in an experiment to observe its effect on the dependent variable. It is not affected by the dependent variable, nor is it kept constant (that's a controlled variable) or used as a control.

Answer:

A. directly changed by the experimenter