5-15 Data collected on the yearly demand for 50-poundbags of fertilizer at Wallace Garden Supply areshown in the following table. Develop a 3-year movingaverage to forecast sales. Then estimate demandagain with a weighted moving average in whichsales in the most recent year are given a weight of 2and sales in the other 2 years are each given a weightof 1. Which method do you think is best?

Years	Bag
1	4
2	6
3	4
4	5
5	10
6	8
7	7
8	9
9	12
10	14
11	15