Refer to the gasoline sales time series data in the given table.

Week	Sales (1000s of gallons)
1	17
2	21
3	19
4	22
5	19
6	15
7	20
8	17
9	21
10	19
11	16
12	22

Compute four-week and five-week moving averages for the time series. Round your answers to two decimal places.

Week	Sales	4-Week Moving Average	5-Week Moving Average
1	17
2	21
3	19
4	22
5	19
6	15
7	20
8	17
9	21
10	19
11	16
12	22

Compute the MSE for the four-week and five-week moving average forecasts. Round your intermediate calculations and final answers to two decimal places. MSE for four-week moving average = MSE for five-week moving average =

What appears to be the best number of weeks of past data (three, four, or five) to use in the moving average computation? Recall that MSE for the three-week moving average is 8.14. Four