McAllister et al. (2012) compared varsity football and hockey players with varsity athletes from noncontact sports to determine whether exposure to head impacts during one season have an effect on cognitive performance. In the study, tests of new learning performance were significantly poorer for the contact sport athletes compared to the noncontact sport athletes. The following table presents data similar to the results obtained in the study.

Noncontact Athletes Contact Athletes 10 7 8 4 7 9 9 3 13 7 7 6 6 10 12 2

a. Are the test scores significantly lower for the contact sport athletes than for the noncontact athletes?

Use a one-tailed test with a 5 .05.

b. Compute the value of r 2

(percentage of variance accounted for) for these data.