Question: To test the effectiveness of a new studying strategy, a psychologist randomly divides a sample of 8 students into two groups, with n= 4 in each group. The students in one group receive training in the new studying strategy. Then all students are given 30 minutes to study a chapter from a history textbook before they take a quiz on the chapter. The quiz scores for the two groups are as follows:

_______________________________________

Training No Training________

9 4

7 7

6 3

10 6

a. Convert these data into a form suitable for the point-biserial correlation. (Use X= 1 for training, X= 0 for no training, and the quiz score for Y.)

b. Calculate the point-biserial correlation for these data.