Walter B. answered • 07/18/18

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First, lets understand what the problem asks for. If we are using a one-tailed test, the significant Z value is 1.68 while the significant Z value for a two tailed test is 1.95. So a Z statistic is 1.8, we would reject a one tailed test, but not a two tailed. Conversely, if the Z statistic is 2.05, we would reject both the two tailed and the one tailed.

Therefore the correct answers are:

**If the two-tailed test is significant, then the one-tailed test at the same α will also be significant (in the appropriate direction).**

**If the one-tailed test is significant, then the two-tailed test at the same α may or may not be significant.**