A researcher conducts a hypothesis test to evaluate the effect of a treatment that is expected to increase scores.The hypothesis test produces a z-score of z = 2.27.If the researcher is using a one-tailed test,what is the correct statistical decision?
A)Reject the null hypothesis with α = .05 but not with α = .01.
B)Reject the null hypothesis with either α = .05 or α = .01.
C)Fail to reject the null hypothesis with either α = .05 or α = .01.
D)Cannot answer without additional information

Question

Quizplus · Accepted Answer

Since it is a one-tailed test, the rejection region is only in one tail of the distribution. Therefore, we need to compare the z-score obtained with the critical value of the normal distribution at the corresponding alpha level. For alpha level of .05, the critical z-value is 1.645. For alpha level of .01, the critical z-value is 2.326. Since the obtained z-score (2.27) is greater than the critical z-value at alpha level of .05 but less than the critical z-value at alpha level of .01, we can reject the null hypothesis with alpha level of .05 but cannot reject it with alpha level of .01.

A Researcher Conducts a Hypothesis Test to Evaluate the Effect