______ would help control for bias in a pretest-posttest design.
A) Increasing the amount of time between the pretest and posttest
B) Including a control group that does not receive the treatment
C) Using fewer subjects
D) Using the posttest scores as the dependent variable

Question

Quizplus · Accepted Answer

By including a control group that does not receive the treatment, any changes observed in the treatment group can be compared to changes in the control group. This helps to control for bias, such as placebo effects or history effects, that may otherwise influence the results of a pretest-posttest design. Increasing the amount of time between the pretest and posttest, using fewer subjects, or using the posttest scores as the dependent variable do not specifically address bias in the design.

______ Would Help Control for Bias in a Pretest-Posttest Design