A researcher conducts a repeated-measures study to evaluate a treatment with a sample of n = 16 participants and obtains a t statistic of t = 1.94.The treatment is expected to increase scores and the sample mean shows an increase.Which of the following is the correct decision for a hypothesis test using α = .05?
A)Reject the null hypothesis with a one-tailed test but fail to reject with two tails
B)Reject the null hypothesis with either a one-tailed or a two-tailed test
C)Fail to reject the null hypothesis with either a one-tailed or a two-tailed test
D)Fail to reject the null hypothesis with a one-tailed test but reject with two tails

Question

Quizplus · Accepted Answer

A t of 1.94 for a sample of 16 participants is significant at α = .05 with a one-tailed test, but not with a two-tailed test. Since the researcher had an a priori hypothesis that the treatment would increase scores, a one-tailed test would be appropriate. Therefore, the null hypothesis should be rejected with a one-tailed test but fail to reject with a two-tailed test.

A Researcher Conducts a Repeated-Measures Study to Evaluate a Treatment