Refer to Example 12.12 in which x = test track speed and y = rolling test speed. a. M...

Refer to Example 12.12 in which x = test track speed and y = rolling test speed.

a. Minitab gave . 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.