If you are hypothesizing that posttest scores will be higher than pretest scores, you should use _______.
A)a one-tailed test
B)a two-tailed test
C)descriptive statistics
D)a t-test for independent means

Question

Quizplus · Accepted Answer

A one-tailed test is appropriate for this hypothesis because it predicts the directionality of the difference between posttest and pretest scores (i.e. higher posttest scores). A two-tailed test would not be appropriate because it does not make a directional prediction. Descriptive statistics can be used to summarize the data, but cannot test the hypothesis directly. A t-test for independent means would not be appropriate if the study used a repeated measures design, in which each participant's pretest and posttest scores are compared directly.

If You Are Hypothesizing That Posttest Scores Will Be Higher