Tuddenham and Snyder obtained the following results for 66 California boys at ages 6 and 18 (the scatter diagram is football-shaped):

average height at \(6 \approx 3\) feet 10 inches, \(SD \approx 1.7\) inches

average height at \(18 \approx 5\) feet 10 inches, \(SD \approx 2.5\) inches, \(r \approx 0.80\)

a) Find the r.m.s. error for the regression prediction of height at 18 from height at 6. b) Find the r.m.s. error for the regression prediction of height at 6 from height at 18.