The flow rate y (m^{3} /min) in a device used for airquality measurement depends on the pressure drop x (in. of water) across the device’s filter. 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 (i.e., true average) change in flow rate associated with a 1-in. increase in pressure drop? Explain.

b. What change in flow rate can be expected when pressure drop increases from 10 in. to 15 in.?

c. What is the expected (i.e., true average) flow rate when the pressure drop is 10 in.? When the pressure drop is 15 in.?

d. Suppose that .025 and consider making repeated observations on flow rate when the pressure drop is 10 in. What is the long-run proportion of observed flow rates that will exceed .835 [that is, what is P(y .835 when x 10)]?