In experimental studies examining the effectiveness of new medications, researchers often administer a placebo (an inactive substance that should have no medical effect on the participant). Giving a placebo to participants in the control condition increases:
A) external validity.
B) internal validity.
C) independence.
D) extraneous variables.

Question

Quizplus · Accepted Answer

Internal validity is increased by using a placebo in the control group because it helps to ensure that the observed effects are due to the experimental treatment and not to participants' expectations or psychological factors.

In Experimental Studies Examining the Effectiveness of New Medications, Researchers