Exhibit 10-9
Two major automobile manufacturers have produced compact cars with the same size engines. We are interested in determining whether or not there is a significant difference in the MPG (miles per gallon) of the two brands of automobiles. A random sample of eight cars from each manufacturer is selected, and eight drivers are selected to drive each automobile for a specified distance. The following data show the results of the test.
Driver | Manufacturer A | Manufacturer B |
1 | 32 | 28 |
2 | 27 | 22 |
3 | 26 | 27 |
4 | 26 | 24 |
5 | 25 | 24 |
6 | 29 | 25 |
7 | 31 | 28 |
8 | 25 | 27 |
Refer to Exhibit 10-9. The mean for the differences is
◦
0.50
◦
1.5
◦
2.0
◦
2.5