4. Refer to the gasoline sales time series data on Forecasting PPT slide 11 of 40 (Use Excel for this problem). a) Compute two- week, three-week, and four- week moving average forecasts for the time series data. Prepare the Time Series Plots. b) Compute Measures of Forecast Accuracy like MAE, MSE, and MAPE. Which method of forecasting of the three (two, three, or four- week moving average models) would you prefer to use for future forecasting purposes? Justify your answer.FIGURE 18.1 GASOLINE SALES TIME SERIES PLOT TABLE 18.1 25 GASOLINE SALES TIME SERIES 20 Sales (1000s Week of gallons) 17 15 21 19 23 10 FE GOD VOUIAWINE 5 O 1 2 3 4 5 6 7 8 9 10 11 12 Week