b.Key in 2nd quarter sales and press 2.

c.Key in 3rd quarter sales and press 3.

d.Key in 4th quarter sales and press 4.

e.Key in the 1st quarter sales for the next year and press 5.

4.Press 00 to calculate the centered moving average for the 3rd quarter of the first year.

5.Press to calculate the seasonal variation for this quarter.

6.Key in the next quarter's sales and press to calculate the moving average for the next quarter.

7.Press to calculate the seasonal variation.

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:

 

Sales (IN $K)

 

 

Quarterly

1st

2nd

3rd

4th

1978

397

376

460

501

1979

455

390

530

560

1980

513

434

562

593

Find the centered 4-quarter moving average and seasonal variation factor for each quarter.

 

Keystrokes

Display

 

 

CLEAR

0.00

 

 

 

 

397

1

397.00

 

 

 

376

2

376.00

 

 

 

460

3

460.00

 

 

 

501

4

501.00

 

 

 

455

5

455.00

 

 

 

 

 

 

Centered 4-element average for

 

00

440.75

3rd quarter, 1978 seasonal

 

 

variation factor.

 

 

 

 

 

104.37

 

 

 

 

 

78

Page 79
Image 79
HP 12C manual Sales in $K Quarterly 1st 2nd 3rd 4th