Refer to the gasoline sales time series data in Table.
a. Compute four- and five-week moving averages for the time series.
b. Compute the MSE for the four- and five-week moving average forecasts.
c. What appears to be the best number of weeks of past data to use in the moving average computation? Remember that the MSE for the three-week moving average is 10.22.
TABLE GASOLINE SALES TIMES SERIES
Week Sales (1000s of gallons)
1 .......... 17
2 .......... 21
3 .......... 19
4 .......... 23
5 ............. 18
6 .......... 16
7 .......... 20
8 .......... 18
9 .......... 22
10 .......... 20
11 .......... 15
12 .......... 22