How do you calculate the Squared Error to get the 81, 49, 1.78?

7. The following historical data have been collected representing sales of a product. Compare forecasts using a three-period moving average, exponential smoothing with an a = 0.2, and linear regression. Using MAD and MSE, which forecasting model is best? Are your results the same using the two error measures? Week Demand 1 20 2 31 3 36 38 42 40 Solution Week Demand 3-period moving average Squared Error Exponential smoothing Absolute Error Squared Error 1 20 2 31 20 11 121 3 36 22.2 13.8 190.44 4 38 29 81 24.96 13.04 170.04 5 35 27.568 14.432 208.28 6 38.67 30.454 9.545 42 40 Absolute Error 9 7 1.33 4 5 6 49 1.78 91.118