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Chapter 7—Specialty Packaging Corporation, Part A
The results for this case are obtained using the accompanying spreadsheet Chapter 7—SPC case study
answer. Given the clear seasonal pattern in the data, the forecast is made using the static forecasting
method (with trend and seasonality) and Winter’s model (both outlined in Chapter 7).
Static Forecasting Method
The result for the static forecasting method is contained in the worksheet Static Forecast. For black
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The various error estimates are shown in Cells I29:P48.
For clear plastic, the methodology used is identical except that the results are shown in Cells A64:Z96.
The static forecast for clear plastic is as follows:
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Winter’s Model
The evaluations for Winter’s model are shown in worksheet Winter. The first step in Winter’s model is to
obtain initial estimates of level, trend, and seasonal factors. This is done exactly as in the Static Forecast