Question

The owner of a chain of mini-markets wants to compare the sales performance of two of her stores, Store 1 and Store 2. Though the two stores have been comparable in the past, the owner has made several improvements to Store 1 and wishes to see if the improvements have made Store 1 more popular than Store 2. Sales can vary considerably depending on the day of the week and the season of the year, so she decides to eliminate such effects by making sure to record each store's sales on the same sample of days. After choosing a random sample of

12

days, she records the sales (in dollars) for each store on these days, as shown in Table 1.

Day	Store 1	Store 2	Difference (Store 1 - Store 2)
1	345	429	-84
2	316	514	-198
3	653	580	73
4	681	653	28
5	266	310	-44
6	571	502	69
7	777	797	-20
8	692	491	201
9	646	701	-55
10	919	785	134
11	618	491	127
12	235	299	-64

Table 1

Based on these data, can the owner conclude, at the

0.10

level of significance, that the mean daily sales of Store 1 exceeds that of Store 2? Answer this question by performing a hypothesis test regarding

μd

(which is

μ

with a letter "d" subscript), the population mean daily sales difference between the two stores. Assume that this population of differences (Store 1 minus Store 2) is normally distributed.

Perform a one-tailed test. Then fill in the table below. Carry your intermediate computations to at least three decimal places and round your answers as specified in the table. (If necessary, consult a list of formulas.)

The null hypothesis:	H0:
The alternative hypothesis:	H1:
The type of test statistic:	(Choose one)Z,t,Chi square, F	Degrees of freedom :
The value of the test statistic: (Round to at least three decimal places.)
The critical value at the 0.10 level of significance: (Round to at least three decimal places.)
At the 0.10 level, can the owner conclude that the mean daily sales of Store 1 exceeds that of Store 2?		Yes	No

Answer 1