A researcher conducts an independent-measures study examining the effectiveness of a group exercise program at an assisted living facility for elderly adults. One group of residents is selected to participate in the program, and a second group serves as a control. After 6 weeks, the researcher records a combined score measuring balance and strength for each individual. The data are as follows:

Control Exercise n = 10 n = 15 M = 12 M = 15.5 SS = 120.5 SS = 190.0
a. Does the exercise program have a significant effect? Use an alpha level of .05, two tails.

b. Compute Cohen�s d to measure the size of the treatment effect.