Different approaches to analyzing pretest-posttest data have their own disadvantages. Which of the following is a disadvantage of using single-factor ANOVA with gain scores?
A) The treatment may interact with the posttest
B) Assumptions of linearity and parallel slopes must be satisfied
C) It does not provide information about pretest differences
D) A significant interaction between the between- and within-subjects IVs needs to be decomposed into main effects before one can interpret the results

Question

Quizplus · Accepted Answer

Single-factor ANOVA with gain scores only provides information about the difference between pretest and posttest scores, without taking into account any differences that may have existed between groups prior to the treatment. This can be a disadvantage if pre-existing group differences may be a factor in the results.

Different Approaches to Analyzing Pretest-Posttest Data Have Their Own Disadvantages