CHAPTER 11
FORECASTING MODELS
Internet Case Study: Human Resources, Inc.
We analyze this case using two different approaches: (1) multiplicative decomposition model on the time-
series data, and (2) regression model.
Multiplicative decomposition model. The results of this analysis are shown in file Ch11 Internet Case
Human Resources.XLS, sheet Decomp. The error graph is also shown. We have time-series data for 36
quarters and there are 4 seasons each year. The resulting MAPE is 8.58%. The error graph indicates that
Regression model. A simple regression model would be to use only the quarter number as the
independent variable. However, since we expect the seasons (and locations) to have an impact on
participation, we need to expand the independent variable set to include the seasons. To do so, we include