PRESS statistics for two different models for the gasoline mileage data were calculated in Problems 11.6 and 11.7. On the basis of the PRESS statistics, which model do you think is the best predictor?

Data From Problem 11.6

In Problem 3.5 a regression model was developed for the gasoline mileage data using the regressor engine displacement x1${\mathrm{????}}_1$ and number of carburetor barrels x6${\mathrm{????}}_6$. Calculate the PRESS statistic for this model. What conclusions can you draw about the model's likely predictive performance?

Data From Problem 3.5

Consider the gasoline mileage data in Table B.3.

Data From Problem 11.7

In Problem 3.6 a regression model was developed for the gasoline mileage data using the regressor vehicle length x8${\mathrm{????}}_8$ and vehicle weight x10${\mathrm{????}}_{10}$. Calculate the PRESS statistic for this model. What conclusions can you draw about the potential performance of this model as a predictor?

Data From Problem 3.6

In Problem 2.4 you were asked to compute a 95$95$ CI on mean gasoline prediction interval on mileage when the engine displacement x1=275${\mathrm{????}}_1=275$ in. 3$3$ Compare the lengths of these intervals to the lengths of the confidence and prediction intervals from Problem 3.5 above. Does this tell you anything about the benefits of adding x6${\mathrm{????}}_6$ to the model?

Data From Problem 2.4

Table B. 3 presents data on the gasoline mileage performance of 32 different automobiles.

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Automobile y x X2 X3 X4 Xs X6 X7 X8 Xg X10 x11 Apollo 18.90 350 165 260 8.0:1 2.56:1 4 Omega 1700 350 170 275 8.5:1 2.56:1 Nova 20.00 250 105 185 8.25:1 2.73:1 Monarch 18.25 351 Duster 20.07 225 Jenson 11.2 440 143 255 8.0:1 3.00:1 95 170 215 330 8.4:1 2.76:1 8.2:1 2.88:1 4 3 4124 3 200.3 69.9 3910 A 3 199.6 72.9 2860 A 3 196.7 72.2 3510 A 2 3 199.9 74.0 3890 A 3 194.1 71.8 3365 M 184.5 69 4215 A Conv. Skyhawk 22.12 231 110 175 8.0:1 2.56:1 2 Monza 21.47 262 110 200 8.5:1 2.56:1 Scirocco 34.70 89.7 70 81 8.2:1 3.90:1 Corolla 30.40 96.9 75 83 9.0:1 4.30:1 2 2222 2 24 33450 179.3 65.4 3020 A 179.3 65.4 3180 A 155.7 64 1905 M 165.2 65 2320 M SR-5 Camaro Datsun 16.50 350 155 250 36.50 85.3 80 83 8.5:1 3.08:1 8.5:1 3.89:1 2 4 42 34 195.4 74.4 3885 A 160.6 62.2 2009 M B210 Capri II 21.50 171 Pacer Babcat 19.70 258 20.30 140 Granada 17.80 302 Eldorado 14.39 500 Imperial 14.89 440 109 146 8.2:1 110 195 8.0:1 83 109 8.4:1 129 220 8.0:1 190 360 215 330 8.2:1 3.22:1 2 4 3.08:1 3.40:1 3.0:1 212N- 170.4 66.9 2655 M 3 171.5 77 3375 A 2 4 168.8 69.4 2700 M 3. 199.9 74 3890 A 8.5:1 2.73:1 4 3 224.1 79.8 5290 A 2.71:1 Nova LN 17.80 350 155 250 8.5:1 3.08:1 Valiant 16.41 318 145 255 8.5:1 2.45:1 Starfire 23.54 231 110 175 8.0:1 2.56:1 Cordoba 21.47 360 180 290 8.4:1 2.45:1 Trans AM 16.59 400 185 NA 76:1 3.08:1 Corolla E-5 31.90 96.9 75 83 9.0:1 4.30:1 Astre 29.40 140 Mark IV 13.27 460 Celica GT 23.90 133.6 Charger SE 19.73 318 Cougar 13.90 351 86 NA 8.0:1 223 366 8.0:1 96 120 8.4:1 140 255 8.5:1 148 243 8.0:1 2.92:1 3.00:1 3.91:1 2 5 2.71:1 3.25:1 Elite 13.27 351 148 243 8.0:1 3.26:1 Matador Corvette 13.77 360 195 295 8.25:1 3.15:1 4422242222224 4 3 231.0 79.7 5185 A 3 196.7 72.2 3910 A 3 1976 71 3660 A 3 179.3 65.4 3050 A 2 3 214.2 76.3 4250 A 3 196 73 3850 A 2 5 165.2 61.8 2275 M 4 176.4 65.4 3 228 2150 M 79.8 5430 A 171.5 63.4 2535 M 3 215.3 76.3 4370 A 3 215.5 78.5 4540 A 2 3 216.1 78.5 4715 A 3 209.3 77.4 4215 A 16.50 350 165 255 8.5:1 2.73:1 4 3 185.2 69 3660 A