1. Summarize the forecast error level for the best method John has found using Minitab.
2. John used the Minitab default values for α, β, and γ. John thinks there are other choices for these parameters that would lead to smaller error measurements. Do you agree?
3. Although disappointed with his initial results, this may be the best he can do with smoothing methods. What should John do, for example, to determine the adequacy of the Winters' forecasting technique?
4. Although not calculated directly in Minitab, the MPE (mean percentage error) measures forecast bias. What is the ideal value for the MPE? What is the implication of a negative sign on the MPE?
John Mosby, owner of several Mr. Tux rental stores, is beginning to forecast his most important business variable, monthly dollar sales (see the Mr. Tux cases in previous chapters). One of his employees, Virginia Perot, gathered the sales data shown in Case 2-2. John now wants to create a forecast based on these sales data using moving average and exponential smoothing techniques.