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Statistics
Curve Fitting
Exponential Curve Fit
Using the ° function of the HP 12C Platinum, a least squares exponential curve fit may
be easily calculated according to the equation y=Ae
Bx
. The exponential curve fitting
technique is often used to determine the growth rate of a variable such as a stock's value
over time, when it is suspected that the performance is non-linear. The value for B is the
decimal value of the continuous growth rate. For instance, assume after keying in several
end-of-month price quotes for a particular stock it is determined that the value of B is
0.10. This means that over the measured growth period the stock has experienced a 10%
continuous growth rate.
If B>0, you will have a growth curve. If B<0, you will have a decay curve.
Examples of these are given below.
The procedure is as follows:
1.
Press
fCLEARH .
2.
For each input pair of values, key in the y-value and press
g°, key in the
corresponding x-value and press
_ .
3.
After all data pairs are input, press
gR~ to obtain the correlation coefficient
(between ln y and x).
Time
Quantity
GROWTH CURVE
(B>0)
Time
Quantity
DECAY CURVE
(B<0)