The research method in which the investigator manipulates a variable under carefully controlled conditions and observes whether any changes occur in a second variable as a result is the

A) scientific method.
B) correlational method.
C) descriptive method.
D) experimental method.

Experimental Method

A research method involving the manipulation of variables to establish cause-and-effect relationships.

Variable Manipulation

The systematic adjustment or alteration of the independent variables in an experiment to observe their effect on the dependent variables.

Controlled Conditions

A methodological practice in experiments where all variables are kept constant except for the independent variable being tested.