The magazine Consumer Reports publishes information on automobile gas mileage and variables that affect gas mileage. In one issue, data on gas mileage (in mpg) and engine displacement (in liters, L) were published for 121 vehicles. Those data are stored on the Weiss Stats CD.
a. Obtain and interpret the standard error of the estimate.
b. Obtain a residual plot and a normal probability plot of the residuals.
c. Decide whether you can reasonably consider Assumptions 1–3 for regression inferences met by the two variables under consideration.