Fuel economy and weight. A consumer organization has reported test data for 50 car models. We will examine the association between the weight of the car (in thousands of pounds) and the fuel efficiency (in miles per gallon). Use the data provided on the disk to answer the following questions, where the response variable is Fuel Efficiency (mpg).

(Data in Fuel economy)

a) Create the scatterplot and obtain the regression equation.

b) Are the assumptions for regression satisfied?

c) Write the appropriate hypotheses for the slope.

d) Test the hypotheses and state your conclusion.