Marla G. answered • 11/07/19

Effective Math tutor Specializing in Statistics

A one-tailed test at alpha=0.01 is equivalent to doing a two-tailed test at alpha=0.005. The value of the test statistic remains the same, but the "cut-off" value changes. Using the same alpha In the two-tailed test, you need to split the alpha in half, and allot 1/2 of alpha in each tail. so the correct answer is D.