In an example we used in Exercises 11.42 and 11.47, we reported data from our statistics classes in which male and female students were asked how long, in minutes, they typically spend getting ready for a date. Here are some of the calculations we needed to conduct the independent-samples t test:

dfX N 1 4 1 3; dfY N 1 4 1 3; dftotal dfX  dfY 3  3 6

a. Calculate the appropriate measure of effect size for this sample.

b. Based on Cohen’s conventions, is this a small, medium, or large effect size?

c. Why is it useful to have this information in addition to the results of a hypothesis test?