Graphing
Exponential regression can be used when y is proportional to the exponential function of x. The normal exponential regression formula is y = a · eb·x. If we obtain the logarithms of both sides, we get ln(y) = ln(a) + b·x. Next, if we say that Y = ln(y) and A = In(a), the formula corresponds to the linear regression formula Y = A + b·x.
uClassPad Operation
Start the graphing operation from the Statistics application’s Graph window or List window.
From the Graph window
Tap [Calc] [Exponential Reg] [OK] [OK] ".
From the List window
Tap [SetGraph][Setting·...], or G.
On the Set StatGraphs dialog box that appears, configure a StatGraph setup with the setting shown below, and then tap [Set].
Type: ExpR
Tap yto draw the graph.
The following is the exponential regression model formula in this case.
y= a · eb·x
a : regression coefficient
b : regression constant term
r : correlation coefficient
r2 : coefficient of determination
MSe : mean square error
•MSe = n 1 2 Σn (ln (yi) – (ln (a) + b·xi ))2–i=1
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