Question

The data in the table represent the weights of various domestic cars and their miles per gallon in the city for the 2008 model year. For these data, the least-squares regression line is y=-0.007x + 44.085. A twelfth car weighs 3,425 pounds and gets 12 miles per gallon.

(a) Compute the coefficient of determination of the expanded data set. What effect does the addition of the twelfth car to the data set have on R^2?

(b) Is the point corresponding to the twelfth car influential? Is it an outlier?

Car   Weight (pounds), x   Miles per Gallon, y
1   3762   20
2   3982   20
3   3533   20
4   3173   21
5   2585   28
6   3731   19
7   2603   27
8   3775   18
9   3312   22
10   2994   27
11   2760   25
      
      
      
      
      
      
      
      
      
      

Answer 1