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12.2: Chapter 5

Last updated

Apr 22, 2025
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- 12.1: Chapter 3
- 12.3: Chapter 6

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Quantitative Problems

Most likely, the period would be 52, as sales probably go through a cycle each year, and there are 52 weeks in the year.

There are peaks in the data at times 1, 5, and 9 as well as minimum points at times 4, 8, and 12, suggesting a period of 4 months.

(728.6, 729.4, 728.6, 727.3, 727.1, 727.0, 726.0, 725.8)
There will be 8 terms in the centered SMA, as shown. These values form the trend-cycle component.

(69.9, −225.3, 159.8, −1.5, 66.3, −228.0, 165.7, −3.8)

(68.1, −226.65, 162.75, −2.65), repeating in blocks of 4

(812.6, 953.85, 635.75, 506.75, 820.3, 952.45, 630.65, 501.65, 823.6, 948.65, 626.35, 504.25)

Since the missing data is due to different reporting policies on different days of the week, an SMA window of 7 days is most appropriate.

See Solution Manual

$\text{Period}=3$ from the ACF plot.

See Solution Manual

Forecasted value for 2024: 1.2124

$\text{MAE}=421.6$ .

$\text{RMSE}=\sqrt{313,168.55}=559.6$ .

$\text{MAPE}=0.123$ , or 12.3%.

$\text{sMAPE}=.0133$ , or 13.3%.

See Solution Manual

Quantitative Problems

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