Period Observed Value Forecast A Forecast B Forecast C Forecast D Forecast E 1 70 - - - - - 2 60 70 75 65 70 100 3 58 65 65 55 60 55 4 62 62 60 50 58 60 5 71 64 68 55 62 70 6 50 68 75 65 71 50 (a) Compute the Mean Absolute Deviation of Forecast B. (b) Compute the Mean Absolute Percent Error of Forecast C. (c) According to the MSE error measure, which Forecast did better, D or E