User Manual

171.393.33 3-month average for March.

131760

144,790.00 3-month average for April.

300500

207,440.00 3-month average for May.

271120

234,460.00 3-month average for June.

Seasonal Variation Factors Based on Centered Moving

Averages.

Seasonal variation factors are useful concepts in many types of forecasting.

There are several methods of developing seasonal moving averages, on the of

more common ways being to calculate them as a ration of the periodic value to a

centered moving average for the same period.

For instance, to determine the sales for the 3rd quarter of a given year a

centered moving average for that quarter would be calculated from sales figures

from the 1st, 2nd, 3rd and 4th quarters of the year and the 1st quarter of the

following year. The seasonal variation factor for that 3rd quarter would then be

the ration of the actual sales in the 3rd quarter to the centered moving average

for that quarter.

While quarterly seasonal variations are commonly used, the HP 12C can also be

programmed to calculate monthly seasonal variations using a centered 12 month

moving averages. Programs for both of these calculations are represented here:

An HP 12C program to calculate the quarterly seasonal variations based on a

centered 4-point moving average is:

KEYSTROKES DISPLAY

CLEAR

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01- 45 1

02- 2

03- 10

04- 45 2

05- 44 1

06- 40

07- 45 3