Defining A Regression Model - HP 39g+ User Manual

Defining a regression model

Angle Setting
To choose the fit
Fit models
8-12
The Symbolic view includes an expression (Fit1 through
Fit5) that defines the regression model, or "fit", to use for
the regression analysis of each two-variable data set.
There are three ways to select a regression model:
•
Accept the default option to fit the data to a straight
line.
•
Select one of the available fit options in Symbolic
Setup view.
•
Enter your own mathematical expression in Symbolic
view. This expression will be plotted, but it will not be
fitted to the data points.
You can ignore the angle measurement mode unless your
Fit definition (in Symbolic view) involves a trigonometric
function. In this case, you should specify in the mode
screen whether the trigonometric units are to be
interpreted in degrees, radians, or grads.
1. In Numeric view, make sure
2. Press
SETUP
view. Highlight the Fit number (S1FIT to S5FIT) you
want to define.
3. Press and select from the list. Press
done. The regression formula for the fit is displayed in
Symbolic view.
Eight fit models are available:
Fit model
Lineair
Logaritmisc
h
Macht
Power
-
to display the Symbolic Setup
SYMB
Meaning
(Default.) Fits the data to a straight
line, y = mx+b. Uses a least-squares
fit.
Fits to a logarithmic curve,
y = m lnx + b.
Fits to an exponential curve,
mx
y = be
.
Fits to a power curve, y = bx
is set.
when
m
.
Statistics aplet