Other factors held constant, a one-tailed test is more powerful than a two-tailed test.

Question

Quizplus · Accepted Answer

A one-tailed test focuses on detecting a difference in one specific direction, while a two-tailed test is used to detect a difference in any direction. By focusing the test on one specific direction, a one-tailed test has a narrower scope and therefore a greater likelihood of detecting a significant difference, making it more powerful than a two-tailed test.

Other Factors Held Constant, a One-Tailed Test Is More Powerful