154 Chapter 4 Estimating and Forecasting Demand
FIGURE 4.4
Fitting a Trend to a
Time Series
Candidates include
linear and nonlinear
trends.
Sales
Time
Qt = 98.2 + 8.6 t
Time
(a) Fitting a Linear Trend
(b) Fitting a Quadratic Trend
Sales
Qt = 101.8 + 7.0 t + .12 t^2
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