The research director of a national supermarket chain asserts that their weekly sales campaign also increase the sales of non-sale items. In order to measure the effect of a storewide sales campaign on non-sale items, the research director took a random sample of 13 pairs of stores that were matched according to average weekly sales volume. One store of each pair was exposed to the sales campaign, and other member of the pair was not The data is given in file Problem5Data.

Store	With Sales Campaign	Without Sales Campaign
1	67.2	65.3
2	59.4	54.7
3	80.1	81.3
4	47.6	39.8
5	97.8	92.5
6	38.4	37.9
7	57.3	52.4
8	75.2	69.9
9	94.7	89.0
10	64.3	58.4
11	31.7	33.0
12	49.3	41.7
13	54.0	53.6

Identify the null and alternative hypotheses for this situation.

Using a 1% significance level, what conclusion can you reach?

Find a 99% confidence interval for the difference between the mean sales of non-sale items for stores exposed to the campaign and those not exposed to the campaign. Does this confidence interval support the conclusion reached by the hypothesis test in part b?