9. The ow rate y (m3/min) in a device used for airquality measurement depends on the pressure drop x (in. of water) across the device s lter. Suppose that for x values between 5 and 20, the two variables are related according to the simple linear regression model with true regression line y  .12  .095x.

a. What is the expected change in ow rate associated with a 1-in. increase in pressure drop?

Explain.

b. What change in ow rate can be expected when pressure drop decreases by 5 in.?

c. What is the expected ow rate for a pressure drop of 10 in.? A drop of 15 in.?

d. Suppose s  .025 and consider a pressure drop of 10 in. What is the probability that the observed value of ow rate will exceed .835? That observed ow rate will exceed .840?

e. What is the probability that an observation on ow rate when pressure drop is 10 in. will exceed an observation on ow rate made when pressure drop is 11 in.?