
b.Key in 2nd quarter sales and press  2.
 2.
c.Key in 3rd quarter sales and press  3.
 3.
d.Key in 4th quarter sales and press  4.
 4.
e.Key in the 1st quarter sales for the next year and press  5.
 5.
4.Press 
 00
 00  to calculate the centered moving average for the 3rd quarter of the first year.
 to calculate the centered moving average for the 3rd quarter of the first year.
5.Press  to calculate the seasonal variation for this quarter.
 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.
 to calculate the moving average for the next quarter.
7.Press  to calculate the seasonal variation.
 to calculate the seasonal variation.
8.Repeat steps 6 and 7 for the balance of the data.
Example: 
| 
 | 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 
| 
 | 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  | 
| 
 | 00 | 440.75 | 3rd quarter, 1978 seasonal | 
| 
 | 
 | variation factor. | |
| 
 | 
 | 
 | |
| 
 | 
 | 104.37 | 
 | 
| 
 | 
 | 
 | 
 | 
78
