Refer to the gasoline sales time series data in the given table. Click on the datafile logo to reference the data. DATA file Week Sales (1,000s of gallons) 17 2 21 19 23 18 16 20 18 22 10 20 11 15 12 22(a) Compute four-week and five-week moving averages for the time series. Do not round intermediate calculations. If required, round your answers to two decimal places. 4-Week 5-Week Week Sales Moving Moving Average Average 17 N 21 19 23 18 6 16 20 18 9 22 10 20 11 15 12 22 X (b) Compute the MSE for the four-week and five-week moving average forecasts. Do not round intermediate calculations. If required, round your answers to two decimal places. MSE for four-week moving average m MSE for five-week moving average =