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. At 90% confidence, a business related recommendation is:
a. There is not enough evidence to show an average difference in MPG between the two manufacturers.
b. No recommendation can be made at this time.
c. The hypothesis test should be conducted again.
d. There is sufficient evidence that an average difference in MPG exists between the two manufacturers.