User Manual

1. Press CLEAR .
2. Key in the first y-value and press
. Key in the first x-value and press
. Repeat this step for each data pair.
3. After all data pairs are input, press
to obtain the correlation coefficient
(between y and ln x).
4. Press 1
0 to obtain A in the equation above.
5. Press
to obtain B.
6. To make a y-estimate, key in the x-value and press
.
Example 1: A manufacturer observes declining sales of a soon-to-be obsolete
product, of which there were originally 10,000 units in inventory. The cumulative
sales figures over a number of months, given below, may be fit by a logarithmic
cure of the form y = A + B (ln x), where y represents cumulative sales in units
and x the number of months since the beginning. How many units will be sold by
the end of eighth months?
Month
1 2 3 4 5 6
Cumulative Sales (units)
1431 3506 5177 6658 7810 8592
Keystrokes Display
CLEAR
1431
1
1.00 First pair data input.
3506
2
2.00 Second pair data input.
5177
3
3.00 Third pair data input.
6658
4
4.00 Forth pair data input.
7810
5
5.00 Fifth pair data input.
8592
6
6.00 Sixth pair data input.