Problem 2 (Note use sheet called Sales+)
Given sales projections (quarterly) for 4 straight years and the advertising costs for the same periods.
Compute a linear regression model and determine if is a good model/fit.
Year	Quarter	Sales	Advertising
1	1	144	41
	2	151	51
	3	134	32
	4	151	45
2	1	145	48
	2	145	34
	3	141	29
	4	166	43
3	1	151	40
	2	164	51
	3	151	39
	4	176	54
4	1	170	41
	2	180	52
	3	156	48
	4	187	47
5	1	166	44
	2	182	48
	3	154	44
	4	169	36