
186 Practical Spreadsheet Risk Modeling for Management
6.20, which show the trend charts
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for the 100 forecast day prices using the
GARCH and MA2 models, respectively.
The moving average model predicts prices in the range of $20–$43, while
the GARCH model exhibits a much narrower range ($25–$35). The reason
that the GARCH model produces a smaller range of forecast prices is because
it picks up the fact that the recent volatility in the stock price has been rela-
tively low. The GARCH model is designed to model changes in volatility over
time, and if you think this is an accurate reection of the stock price behav-
ior, it would be a good foreca ...