If you have an experimental manipulation that you hypothesize will decrease scores, then for you to be able to reject the null hypothesis, your observed z-score must be:
A) Negative
B) Positive
C) Zero
D) There is insufficient information to make conclusions about the z-score.

Question

Quizplus · Accepted Answer

A negative z-score is indicative of a decrease in scores. Since the manipulation hypothesis is predicting a decrease in scores, a negative z-score is necessary to reject the null hypothesis.

If You Have an Experimental Manipulation That You Hypothesize Will