Question

Week	Sales (100s of gallons)
1	18
2	22
3	19
4	24
5	17
6	16
7	21
8	19
9	23
10	21
11	15
12	21

a. using a weight of 1/2 for the most recent observation, 1/3 for the second most recent observation, and 1/6 for the third most recent observation, compute a three-week weighted moving average for the time series (to 2 decimals). Enter negative values as negative numbers.

Weighted Moving Average Forecast Forecast Error Week Time-Series Value (Error) 1 18 ♡ 20.33 4.5 20.25 20.33 22.33 20.33 22.33 -4.83 23.33 20.33 -2.67 7.13 18 ♡ .33 .11 18.83 18.67 4.33 18.75 19.83 1.17 1.37 20.50 20.50 ♡ -6.50 42.25 17.50 2.33 5.43 Total 121.85 ®

b. compute the MSE for the weight moving average in part (a).

MSE=

Answer 1

week	sales	forecast	error	error^2
1	18
2	22
3	19
4	24	19.83	4.17	17.36
5	17	22.00	-5.00	25.00
6	16	19.67	-3.67	13.44
7	21	17.67	3.33	11.11
8	19	18.67	0.33	0.11
9	23	19.17	3.83	14.69
10	21	21.33	-0.33	0.11
11	15	21.33	-6.33	40.11
12	21	18.33	2.67	7.11
			total	129.04

b )

MSE = 14.34