HP 39g+ - Manual (Page 107)

Statistics aplet 8-13
To define your
own fit
1. In Numeric view, make sure is set.
2. Display the Symbolic view.
3. Highlight the Fit expression (Fit1, etc.) for the
desired data set.
4. Type in an expression and press .
The independent variable must be X, and the
expression must not contain any unknown variables.
Example:
.
This automatically changes the Fit type (S1FIT, etc.) in
the Symbolic Setup view to User Defined.
Computed statistics
One-variable
Quadratic Fits to a quadratic curve,
y = ax
2
+bx+c. Needs at least three
points.
Cubic Fits to a cubic curve,
y = ax
3 +bx 2 +cx+d. Needs at least
four points.
Logistic Fits to a logistic curve,
,
where L is the saturation value for
growth. You can store a positive
real value in L, or—if L=0—let L be
computed automatically.
User
Defined Define your own expression (in
Symbolic view.)
Fit model Meaning (Continued)
y
L
1 ae
bx – ( )
+
-------------------------- =
1.5 x cos × 0.3 x sin × +
Statistic Definition
N
Σ Number of data points.
TOT
Σ Sum of data values (with their
frequencies).