Homework SourseThe data on 30 of the bestselling cars in the United States
The data on 30 of the best-selling cars in the United States. We are interested in the relationship between highway mileage and curb weight of the vehicles.
a)Develop a scatter plot for these data. Discuss what the plot implies about the relationship between the two variables. Assume that you wish to predict highway mileage by using vehicle curb weight.
b)Compute the correlation coefficient for the two variables and test to determine whether there is a linear relationship between the curb weight and the highway mileage of automobiles.
c)(1) Compute the linear regression equation based on the sample data. (2) A CTS Sedan weighs approximately 4,012 pounds. Provide an estimate of the average highway mileage you would expect to obtain from this model.
| mileage, highway | mileage,city | Curb Weight | cylinders | Horse Power | Torque | 0 to 60 mph | Price as Tested | Displacement | Car Type | ABS Brakes | Company | |
| Dodge Stratus ES | 29 | 20 | 3320 | 6 | 168 | 170 | 9.4 | 20485 | 2.5 | 1 | 1 | 1 |
| Ford Taurus SE | 28 | 19 | 3426 | 6 | 200 | 200 | 8.7 | 23000 | 3 | 1 | 1 | 2 |
| Cherolet Malibu LS | 29 | 20 | 3060 | 6 | 155 | 185 | 8.8 | 18815 | 3.1 | 1 | 1 | 13 |
| Ford Contour GL | 32 | 24 | 3020 | 4 | 125 | 130 | 11.9 | 18565 | 2 | 1 | 3 | 2 |
| Honda Accord LX | 30 | 23 | 3220 | 4 | 150 | 152 | 9.4 | 20015 | 2.3 | 1 | 1 | 3 |
| Mazda 626 LX | 31 | 23 | 2870 | 4 | 125 | 127 | 11.4 | 19800 | 2 | 1 | 3 | 4 |
| Nissan Altima GXE | 30 | 22 | 3220 | 4 | 150 | 154 | 9.8 | 19508 | 2.4 | 1 | 3 | 5 |
| Oldsmobile Cutlass GLS | 29 | 20 | 3220 | 6 | 150 | 180 | 8.5 | 19970 | 3.1 | 1 | 1 | 6 |
| Toyota Camry LE | 30 | 23 | 3180 | 4 | 133 | 147 | 11 | 21299 | 2.2 | 1 | 1 | 7 |
| BMW 328i | 27 | 19 | 3320 | 6 | 193 | 206 | 7.8 | 38545 | 2.8 | 2 | 1 | 8 |
| Saab 9-5 | 26 | 18 | 3600 | 6 | 200 | 229 | 7.9 | 39250 | 3 | 2 | 1 | 9 |
| Cadillac Catera | 24 | 18 | 3860 | 6 | 200 | 192 | 9.3 | 37708 | 3 | 2 | 1 | 10 |
| Acura TL | 27 | 19 | 3450 | 6 | 225 | 216 | 7.9 | 28514 | 3.2 | 2 | 1 | 11 |
| Volvo S-80 | 27 | 18 | 3700 | 6 | 268 | 280 | 7.3 | 43755 | 2.8 | 2 | 1 | 12 |
| Chevrolet S-10 | 22 | 17 | 3600 | 6 | 175 | 240 | 9.2 | 21532 | 4.3 | 3 | 1 | 13 |
| Dodge Dakota | 21 | 16 | 3900 | 6 | 175 | 225 | 11.2 | 21100 | 3.9 | 3 | 3 | 1 |
| Ford Ranger | 21 | 17 | 3560 | 6 | 158 | 223 | 8.8 | 20740 | 4 | 3 | 1 | 2 |
| Nissan Frontier | 24 | 20 | 3240 | 4 | 143 | 154 | 10.7 | 19589 | 2.4 | 3 | 2 | 5 |
| Toyota Tacoma | 23 | 19 | 3520 | 6 | 190 | 220 | 9.2 | 20990 | 3.4 | 3 | 3 | 7 |
| Chevrolet Silverado LT | 20 | 16 | 4620 | 8 | 270 | 315 | 8.8 | 28000 | 5.3 | 4 | 1 | 13 |
| Dodge Ram Sport | 18 | 13 | 4860 | 8 | 230 | 300 | 9.9 | 26185 | 5.2 | 4 | 2 | 1 |
| GMC Sierra SLT | 21 | 16 | 4480 | 8 | 255 | 285 | 9.9 | 27500 | 4.8 | 4 | 1 | 16 |
| Ford F150 Lariat | 18 | 14 | 4610 | 8 | 260 | 345 | 8.4 | 30240 | 5.4 | 4 | 1 | 2 |
| Acura NSX | 21 | 18 | 3016 | 6 | 290 | 224 | 4.5 | 88136 | 3.2 | 5 | 1 | 11 |
| BMW 540i sport | 22 | 17 | 3740 | 8 | 282 | 310 | 5.5 | 56512 | 4.4 | 5 | 1 | 8 |
| Chevrolet Camaro Z28 SS | 23 | 19 | 3448 | 8 | 320 | 345 | 4.9 | 27141 | 5.7 | 5 | 1 | 13 |
| Chevrolet Corvette | 28 | 18 | 3264 | 8 | 345 | 350 | 4.7 | 42328 | 5.7 | 5 | 1 | 13 |
| Dodge Viper GTS | 21 | 11 | 3420 | 10 | 450 | 490 | 3.9 | 73129 | 8 | 5 | 3 | 1 |
| Jaguar XJR | 19 | 16 | 4006 | 8 | 370 | 387 | 5 | 70219 | 4 | 5 | 1 | 14 |
| Porsche 911 Carrera | 24 | 19 | 3116 | 6 | 296 | 258 | 4.8 | 74178 | 3.6 | 5 | 1 | 15 |
Solution
b) correlation is -0.739
c)
| Regression Analysis | ||||||
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