Forecasting Exercise: Double Exponential Smoothing a. Given the following demand data and the parameters (highlighted), calculate FIT for periods 1 to 9 by using the double exponential smoothing method. b. Using your last Ft and Tt, forecast demand for periods 10, 15, and 20. c. Assess the accuracy of your forecasts using CFE, bias, MAD, and MAPE. Formulas: 1. FIT = Ft + Tt 2. Ft = FITT-1 + a(At-1 - FITt-1) 3. Tt = Tt-1 + B(Ft-Ft-1-Tt-1) (OR: Tt = Tt-1 + aB(At-1-FITt-1)) 4. FITE-n = Ft+1 + n x Tt+1 (e.g. t is the last period with actual demand, when t = 8, n = 2, FIT 8+2 = F8+1 + 2 x T8+1) Period At Ft T F ITT Error ABSE %E Parameters: 100.00 10.00 alpha= 0.4 beta = 0.25 F1 = 100 WN- Accuracy: CFE = Avg Error = MAD MAPE= =SUM(Errors for all periods) =AVG(Errors for all periods) =AVG(Errors for all periods) =AVG(ERROR/A, for all periods) * 100% 8 o O