Problem 1.76 The table below records the curbside weight (in units of 1000 lbs), fuel consumption in miles per gallon (mpg), engine displacement (disp), and fuel consumption in gallons per 100 miles (gpm) for 18 2004-05 model year automobiles. (Displacement is a measure of the size, in liters, of the automobile engine.)

(a) Draw the scatter plot of mpg (y) vs. car weight (x).

(b) Calculate the least squares estimates b0 and b1 and draw the graph of the regression line y = b0 + b1x. Use the same axes on which you graphed the scatter plot.

(c) Compute the fitted values for x = 3.39, 4.07, 5.59.

(d) What is the effect on an automobile’s fuel efficiency (mpg) if its weight is increased by 500 lbs? Automobile Weight mpg Disp gpm Acura RL 3.86 25 3.5 4.000 Acura RSX 2.78 31 2 3.226 Acura TL 3.565 27 3.2 3.704 Audi A4 3.745 23 3 4.348 Audi A8 4.505 20 4.2 5.000 BMW3 3.39 26 3 3.846 BMW5 3.65 24 3 4.167 BMW7 4.505 21 4.4 4.762 Buick LeSabre 3.64 25 3.8 4.000 Buick Park Avenue 3.97 26 3.8 3.846 Cadillac CTS 3.62 24 3.2 4.167 Cadillac DeVille 4.07 23 4.6 4.348 Chevy Impala 3.655 24 3.8 4.167 Chevy Malibu 3.29 31 3.5 3.226 Chevy Suburban 5.59 17 5.3 5.882 Ford Crown Victoria 4.18 21 4.6 4.762 Infiniti FX 4.295 21 3.5 4.762 Lexus GX470 4.825 18 4.7 5.556