(c) We now focus on forecasting beyond 1989. In the follow- ing, continue to use all but the last year as the training period and the last four quarters as the validation period. Apply Holt-Winter's exponential smoothing to the training period. i. Compute MAPE values for the training and validation periods using Holt-Winter's exponential smoothing. ii. Draw two time plots: one for the actual and forecasted values and the other for the residuals. The x-axis should include the training and validation periods. Comment on the model fit in the training and validation periods. iii. If we optimize the smoothing constants in the Holt- Winter's method, are the optimal values likely to be close to zero? Why or why not