HP 12C Financial Programmable Calculator Instrukcja Użytkownika Pobierz pdf (Strona 106)

105

Power Curve Fit

Another method of analysis is the power curve or geometric curve. The

equation of the power curve is y = Ax

, 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 hasfallen, he might have released a rock from various

0.99

Correlation coefficient (between y

and ln x).

1 0

1,066.15 Value of A.

4,069.93 Value of B.

9,529.34

Total units sold by end of eighth

month.

1 2 ... 101 102 103 104 105 106 107 108 109 110 111 ... 164 165

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HP 12C Financial Programmable Calculator Instrukcja Użytkownika Strona 106