Question: An instructor asked five students how many hours they had studied for an exam. (For part f, assume that hours studied is the predictor variable.) Here are the numbers of hours studied and the students’ grades:

Hours Studied Test Grade

0 52
10 95
6 83
8 71
6 64

(a) Make a scatter diagram of the raw scores

(b) Describe in words the general pattern of association, if any

(c) Figure the correlation coefficient

(d) Explain the logic of what you have done, writing as if you were speaking to someone who has never had a statistics course (but who does understand the mean, standard deviation, and Z scores)

(e) Give three logically possible directions of causality, saying for each whether it

was a reasonable direction in light of the variables involved (and why)

(f) Make raw score predictions on the criterion variable for persons with scores

on the predictor variable of –2, –1, 0, +1, and +2

(g) Give the proportion of variance accounted for (R2).