For all students at Walden University, the prediction equation for y = college GPA (range 0–4.0) and x1 = high school GPA (range 0–4.0) and x2 = college board score (range 200–800) is = 0.20 + 0.50x1 + 0.002x2.
a. Find the predicted college GPA for students having (i) high school GPA = 4.0 and college board score = 800 and (ii) x1 = 2.0 and x2 = 200.
b. For those students with x2 = 500, show that  = 1.20 + 0.50x1.
c. For those students with x2 = 600, show that  = 1.40 + 0.50x1. Thus, compared to part b, the slope for x1 is still 0.50, and increasing x2 by 100 (from 500 to 600) shifts the intercept upward by 100 (slope for x2) = 100(0.002) = 0.20 units.