HP 12c Solutions Handbook page 79

b. Key in 2nd quarter sales and press
c. Key in 3rd quarter sales and press
d. Key in 4th quarter sales and press
e. Key in the 1st quarter sales for the next year and press
4. Press
the 3rd quarter of the first year.
5. Press
6. Key in the next quarter's sales and press
average for the next quarter.
7. Press
8. Repeat steps 6 and 7 for the balance of the data.
Example: Econo-Wise Home Appliance Company had quarterly sales for
the years 1978 thru 1980 as follows:
1978
1979
1980
Find the centered 4-quarter moving average and seasonal variation factor
for each quarter.
Keystrokes
CLEAR
397 1
376 2
460 3
501 4
455 5
00
00 to calculate the centered moving average for
to calculate the seasonal variation for this quarter.
to calculate the seasonal variation.
Sales (IN $K)
Quarterly 1st
397
455
513
Display
0.00
397.00
376.00
460.00
501.00
455.00
440.75
104.37
3.
4.
to calculate the moving
2nd 3rd
376 460
390 530
434 562
Centered 4-element average for
3rd quarter, 1978 seasonal
variation factor.
78
2.
4th
501
560
593
5.