In Example 7, we applied trend-adjusted exponential smoothing to forecast demand for a piece of pollution-control equipment for months 2 and 3 (out of 9 months of data provided).

Let us now continue this process for month 4. We want to confirm the forecast for month 4 shown in Table 4.2 (p. 155) and Figure 4.3 (p. 155).

For month 4, A4 = 19, with a = .2, and b = .4.