A research analyst for an oil company wants to develop a model to predict miles per gallon based on highway speed. An experiment is designed in which a test car is driven at speeds ranging from 10 miles per hour to 75 miles per hour.

a) Set up a scatter diagram for speed and miles per gallon.

b) Apply simple regression analysis, and then interpret the meaning of the slope b₁ in this problem.

c) Interpret the meaning of the regression coefficient b₀ in this problem.

d) Determine the coefficient of determination, r², and interpret its meaning.

e) How useful do you think this regression model is for predicting mileage?