Refer to Example 12.12 in which x = test track speed and y = rolling test speed.
a. Minitab gave S 0 + 0 (45) = .120 and S 0 + 0 (47) = .186.
Why is the former estimated standard deviation smaller than the latter one?
b. Use the Minitab output from the example to calculate a 95% CI for expected rolling speed when test speed = 45.
c. Use the Minitab output to calculate a 95% PI for a single value of rolling speed when test speed = 47.