When choosing between one-tailed and two-tailed tests,
A)use a one-tailed test only if you have a convincing reason for predicting the direction.
B)always use two-tailed tests.
C)use a two-tailed test only if you have a convincing reason for not predicting a direction.
D)use the one that is most likely to produce significant results.

Question

Quizplus · Accepted Answer

It is important to have a convincing reason for predicting the direction before using a one-tailed test, otherwise it may result in a biased inference. Therefore, always use a two-tailed test unless there is a clear theoretical or logical justification for using a one-tailed test. Choosing the one that is most likely to produce significant results is not a valid criterion for selecting between one-tailed and two-tailed tests.

When Choosing Between One-Tailed and Two-Tailed Tests