When we conduct a one-tailed test instead of a two-tailed test, there are small changes in
steps 2 and 4 of hypothesis testing. (
For this example, assume that those from
populations other than the one on which it was normed will score lower, on average. That
is, hypothesize that the Canadians will have a lower mean.) Conduct steps 2, 4, and 6 of
hypothesis testing for a one-tailed test.
Under which circumstance—a one-tailed or a two-tailed test—is it easier to reject the null
If it becomes easier to reject the null hypothesis under one type of test (one-tailed versus
two-tailed), does this mean that there is a bigger difference between the groups with a
one-tailed test than with a two-tailed test? Explain.
When we change the
level that we use as a cutoff, there is a small change in step 4 of
hypothesis testing. Although 0.05 is the most commonly used
level, other values, such