Twenty stores in a statewide retail chain are surveyed. The table shows the total number of sales per store (expressed in thousands of dollars) and also the traffic count (number of cars that pass the store per day, expressed in thousands). The table also shows whether the store is located in the north or south regions of the country. Refer to the TRAFFIC COUNTS Excel spreadsheet. 

a. Do sales depend on traffic count? On the region of the country (north or south)? On both?

b. State the null and alternate hypotheses.

c. Conduct the appropriate statistical test to test these hypotheses.

d. Did you find a significant relationship between sales and traffic count? If yes, carefully interpret the coefficient you obtained, in plain English.

e. Did you find a significant relationship between sales and the region of the country? If yes, carefully interpret the coefficient you obtained, in plain English.

f. What percentage of the variation in sales is accounted for in your best model? How do you know?

Store ID	Annual Sales in	Average Daily Traffic	Store Location
Number	Thousands of Dollars	Count in Thousands	by Region
STORE	SALES	TRAFFIC	REGION
1	1021	62	N
2	622	35	N
3	693	36	N
4	1204	72	N
5	850	41	N
6	790	39	N
7	929	49	N
8	493	25	N
9	772	41	N
10	801	39	N
11	854	35	S
12	568	27	S
13	921	55	S
14	699	38	S
15	497	24	S
16	657	28	S
17	1009	53	S
18	976	55	S
19	844	33	S
20	821	29	S