In conducting a z-test with a nondirectional alternative hypothesis, we would
A) use a two-tailed test.
B) use a one-tailed test.
C) not divide the alpha level in two.
D) both "b" and "c" are correct.

Question

Quizplus · Accepted Answer

A nondirectional alternative hypothesis suggests that the true population mean may differ from the hypothesized mean in either direction. Therefore, it requires a two-tailed test to compare the sample mean to the hypothesized mean. In such a test, the rejection region is split into two equal areas, one in each tail of the distribution, and the critical values are determined based on the desired alpha level (e.g., 0.05, 0.01). Dividing the alpha level by two would only be necessary for a directional alternative hypothesis, which specifies a difference in a particular direction (e.g., greater than or less than the hypothesized mean).

In Conducting a Z-Test with a Nondirectional Alternative Hypothesis, We