9781118041581

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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