Name a disadvantage of using a onetailed test instead of a t

Name a disadvantage of using a one-tailed test instead of a two-tailed test.

Solution

A one-tailed test is used when we predict the direction of the difference in advance.

The disadvantage of a one-tailed test is that it precludes any chance of discovering that reality is just the opposite of what the alternative hypothesis stats.

It is not correct to perform a one-tailed test when we want to test whether any difference exists.