Seasonal Variation Factors Based On Centered Moving Averages - HP 12c Solutions Handbook

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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
CLEAR
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171,393.33 3-month average for March.
144,790.00 3-month average for April.
207,440.00 3-month average for May.
234,460.00 3-month average for June.
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