12.95 Multiple choice: Interpret r One can interpret r = 0.30 or the corresponding r2 = 0.09 as follows:

a. A 30% reduction in error occurs in using x to predict y.

b. A 9% reduction in error occurs in using x to predict y compared to using y to predict y.

c. 9% of the time yn = y.

d. y changes 0.3 unit for every one-unit increase in x.

e. x changes 0.3 standard deviations when y changes 1 standard deviation.