45. Following are data on price, curb weight, horsepower, time to go from 0 to 60 miles per hour, and the speed at ¹⁄₄ mile for 16 sports and GT cars.

Curb Speed at Price Weight Horse- 0 to 60 ¹⁄₄ mile Car ($1000s) (lb.) power (seconds) (mph) Acura Integra Type R 25.035 2577 195 7.0 90.7 Acura NSX-T 93.758 3066 290 5.0 108.0 BMW Z3 2.8 40.900 2844 189 6.6 93.2 Chevrolet Camaro Z28 24.865 3439 305 5.4 103.2 Chevrolet Corvette Convertible 50.144 3246 345 5.2 102.1 Dodge Viper RT/10 69.742 3319 450 4.4 116.2 Ford Mustang GT 23.200 3227 225 6.8 91.7 Honda Prelude Type SH 26.382 3042 195 7.7 89.7 Mercedes-Benz CLK320 44.988 3240 215 7.2 93.0 Mercedes-Benz SLK230 42.762 3025 185 6.6 92.3 Mitsubishi 3000GT VR-4 47.518 3737 320 5.7 99.0 Nissan 240SX SE 25.066 2862 155 9.1 84.6 Pontiac Firebird Trans Am 27.770 3455 305 5.4 103.2 Porsche Boxster 45.560 2822 201 6.1 93.2 Toyota Supra Turbo 40.989 3505 320 5.3 105.0 Volvo C70 41.120 3285 236 6.3 97.0

a. Develop an estimated regression equation with price, curb weight, horsepower, and time to go from 0 to 60 mph as four independent variables to predict the speed at ¹⁄₄ mile.

b. Use the F test to determine the significance of the regression results. At a .05 level of significance, what is your conclusion?

c. Use the t test to determine the significance of each independent variable. At a .05 level of significance, what is your conclusion?

d. Delete any independent variable that is not significant and provide your recommended estimated regression equation.