13. You are conducting a study to see if students do better when they study all at

once or in intervals. One group of 12 participants took a test after studying for

one hour continuously. The other group of 12 participants took a test after

studying for three twenty minute sessions. The first group had a mean score of

75 and a variance of 120. The second group had a mean score of 86 and a

variance of 100.

a. What is the calculated t value? Are the mean test scores of these two groups

significantly different at the .05 level?

b. What would the t value be if there were only 6 participants in each group?

Would the scores be significant at the .05 level?