In a randomized subjects pretest-posttest control group design, results might best be analyzed through
A) ANCOVA.
B) ANOVA.
C) change scores.
D) t tests.

Question

Quizplus · Accepted Answer

ANCOVA (Analysis of Covariance) is the best choice because it can control for and adjust for any pre-existing differences between the groups. This is important in a pretest-posttest design where the pre-existing differences could be the reason for the posttest differences. ANOVA and t-tests can only compare means between the groups and do not account for any pre-existing differences. Change scores can be used, but they do not control for pre-existing differences, so ANCOVA is still the preferred method.

In a Randomized Subjects Pretest-Posttest Control Group Design, Results Might