(1)Bivariate regression.Agresti & Finlay p. 289, problem 9.6 (4 points; 2 points for each answer)

A study of mail survey response rate patterns of the elderly found a prediction equation relating x = age (between about 60 and 90) and y = percentage of subjects responding of = 90.2 - 0.6x.

(a)Interpret the slope.

(b)Find the predicted response rate for a (i) 60-year-old, (ii) 90-year-old.

(2)Bivariate regression.Agresti & Finlay p. 289, problem 9.8 (4 points; 2 points for each answer)

A college admissions officer uses regression to approximate the relationship between y = college GPA and x = high school GPA (both measured on a four-point scale) for students at that college.

(a) Which equation is more realistic: = 0.5 + 7.0x, or = 0.5 + 0.7x? Why?

(b) Suppose the prediction equation is = x. Identify the y-intercept and slope, and interpret the slope.