a) 3

b) 4

c) 5

Problem 15-07 (Algorithmic) Refer to the gasoline sales time series data in the given table. Week 1 2 3 4 5 6 7 8 9 10 11 12 Sales (1000s of gallons) 18 21 19 23 17 15 22 19 21 20 16 23 a. Compute four-week and five-week moving averages for the time series. Round your answers to two decimal places. Week 1 2 3 4 5 6 7 8 9 10 11 12 Sales 18 21 19 23 17 15 22 19 21 20 16 23 4-Week Moving Average Moving Average 5-Week b. 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 = c. 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 11.51