The demand for fertilizer at Soil CO. is highly seasonal. The company has gathered the following data over the past few years.

Year	Quarter	Sales
1	1	38
	2	165
	3	82
	4	115
2	1	47
	2	183
	3	74
	4	116
3	1	41
	2	177
	3	89
	4	135
4	1	51
	2	184
	3	92
	4	133
5	1	51
	2	?

1. Plot the quarterly data plus 4-period moving averages.
2. Calculate 4-period moving averages.
3. Use a linear regression model to determine the trend of the quarterly demand for fertilizer.
4. Determine the seasonal factors for each quarter.
5. Calculate the seasonally adjusted forecast for Year 5, quarters 2, 3 and 4.

USE EXCEL AND SHOW EXCEL FORMULAS