User Manual

0.99
Correlation coefficient (between y and ln x).
1 0
1,066.15
Value of A.
4,069.93
Value of B.
8
9,529.34 Total units sold by end of eighth month.
Power Curve Fit
Another method of analysis is the power curve or geometric curve. The equation
of the power curve is y = Ax
B
, and the values for A and B are computed by
calculations similar to linear regression. Some examples of power curves are
shown below.
The following keystrokes fit a power curve according to the equation ln y = ln A +
B(ln x):
1. Press CLEAR .
2. Key in the first y-value and press
. Key in the first x-value and press .
Repeat this step for all data pairs.
3. Press
, to obtain the correlation coefficient (between ln y and ln x).
4. Press 0
to obtain A in the above equation.
5. Press 1
0 to obtain B.
6. To make a y-estimate, key in the x-value and press
.
Example: If Galileo had wished to investigate quantitatively the relationship
between the time (t) for a falling object to hit the ground and the height (h) it has
fallen, he might have released a rock from various levels of the Tower of Pisa