Agroup of freshman football players was told that they had to bulk up in order to have any chance of playing on the varsity the following year. The group was randomly divided into two groups, and for three months the young men were subjected to a strict weight-training program. Group 1, however, was also given a daily dose of a special dietary supplement which was alleged to increase muscle mass. Group 2 was given an identical-appearing placebo. The data follow (all values given in pounds of weight increase):

Group 1: 15, 20, 30, 28, 32; Group 2: 10, 29, 34, 20, 27.

a. Do you reject the null hypothesis?

b. Is there a significant difference in the weight scores between the two groups of subjects?

c. What type of research is this, post facto or experimental?

d. Identify both the IV and DV.

e. If the t ratio was significant, calculate the effect size.