Question: A marketing research firm wishes to compare the prices charged by two supermarket chains. The research firm using a standard shopping list of ten identical purchases at ten of each of the chains stores. The stores for each chain are randomly selected and the data is below:

Chain #A Chain #B

119.25 111.99

123.71 116.62

121.32 114.88

121.72 115.38

122.34 115.11

122.42 114.40

120.14 117.02

123.63 113.91

122.19 116.89

122.43 111.87

a. Consider these samples as random samples and two tailed test to test the difference of two means. Determine your null and alternative hypothesis. Use a pooled standard deviation. (Hint: Minitab can do all the tedious calculations for you. Input your two columns of data into the Minitab worksheet; Go to Stats, then basic stats; under basic stats click on two sample t and continue.)

b. Test using alphas of .10, .05,.01 and .001.

c. Compute a 95% confidence interval for the difference of two means. Again, you can get the interval from your output.