Data collected on the yearly demand for 50-pound bags of fertilizer at Wallace Garden Supply are shown in the following table. Develop a 3-year moving average to forecast sales. Then estimate demand again with a weighted moving average in which sales in the most recent year are given a weight of 2 and sales in the other 2 years are each given a weight of 1. Which method do you think is best? The Mean Absolute Deviation (MAD) for the above moving average forecast? What is the three-year weighted moving average forecast for Wallace Garden Supply ? What is the Mean Absolute Deviation (MAD) for the above weighted moving average forecast?
DEMAND FOR FERTILIZER
YEAR (1,OOOS OFBAGS)
1 4
2 6
3 4
4 5
5 10
6 8
7 7
8 9
9 12
10 14
11 15