In a one-sample z test,when you have evidence or reasoning to suggest that your sample mean will most likely differ from the hypothesized population value in one direction (for example,"it will be higher than the hypothesized value"),you would use a
A)nondirectional ("two-tailed")test
B)directional ("one-tailed")test
C)more stringent alpha level
D)both a and c

Question

Quizplus · Accepted Answer

A directional ("one-tailed") test would be the best choice in this situation because you have a specific prediction about the direction of the difference between the sample mean and hypothesized population value. Using a one-tailed test allows for greater statistical power to detect the predicted difference. Additionally, there is no need for a more stringent alpha level since a one-tailed test already increases the chance of Type I error by focusing only on one direction of the distribution.

In a One-Sample Z Test,when You Have Evidence or Reasoning