Question

Problem 15-08 (Algorithmic) Refer again to the gasoline sales time series data in the following table. Week Sales (1000s of gallons)
I just need help with those marked with a red X, and the last question thank you!

Answer 1

Answer: 15-08 (Algorithmic) Refer again to the gasoline sales time series data in the following table.

Solution:

a)

Week	sales	weight moving average forecast	Forecast Error	(Error)2
1	19
2	24
3	19
4	25	20.67	4.33	18.75
5	19	22.83	-3.83	14.67
6	16	21.00	-5.00	25
7	21	18.50	2.50	6.25
8	17	19.00	-2.00	4
9	22	18.17	3.83	14.67
10	21	20.17	0.83	0.69
11	15	20.67	-5.67	32.15
12	24	18.17	5.83	33.99
				150.17

b) MSE = Total of (Error)2 / no. of week consider forecast

MSE = 150.17/9

MSE = 16.69

c) As weighted average is better as unweighted average. Therefore, Yes, we can find a set of weights that would make a MSE smaller for weighted average then unweighted moving average when weights are equal.

As per requirement I correct only those parts which are wrong. So, if you like please appreciate.