Question

Two major automobile manufacturers have produced compact cars with engines of the same size. We are interested in determining whether or not there is a significant difference in the mean MPG (miles per gallon) when testing for the fuel efficiency of these two brands of automobiles. A random sample of eight cars from each manufacturer is selected. The following data (in miles per gallon) show the results of the test. Assume the population of differences is normally distributed.

Manufacturer A	Manufacturer B
32	28
27	22
26	27
26	24
25	24
29	25
31	28
25	27

Complete the following table (round numbers to two decimal places):

	Manufacturer A	Manufacturer B
Mean
Variance
t-Stat (test statistic)
p-value (two tail)
t critical value (two tail)

Using a .05 level of significance, test to see if there is a significant difference between the two manufacturers. What do you conclude?

Answer 1