Suppose these data show the number of gallons of gasoline sold by a gasoline distributor in Bennington, Vermont, over the past 12 weeks. Sales (1,000s of gallons) 18. Week 1 2 3 st 4 5 6 7 8 9 10 11 12 21 19 24 19 16 21 19 22 20 16 22 (a) Compute four-week and five-week moving averages for the time series. 5-Week Moving Average Forecast Week 1 2 3 st 4 5 6 7 00 8 9 10 11 12 Time Series Value 18 21 19 24 19 16 21 19 22 20 16 22 4-Week Moving Average Forecast (b) Compute the MSE for the four-week moving average forecasts. (Round your answer to two decimal places.) Compute the MSE for the five-week moving average forecasts. (Round your answer to two decimal places.)