HP 39g+ Graphing manual Computed statistics, To define your own fit

To define your own fit

Fit model	Meaning (Continued)
Quadratic	Fits to a quadratic curve,
	y = ax2+bx+c. Needs at least three
	points.
Cubic	Fits to a cubic curve,
	y = ax3+bx2+cx+d. Needs at least
	four points.
Logistic	Fits to a logistic curve,
	L
	y = -------------------------- ,
	1 + ae(–bx)
	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	Define your own expression (in
Defined	Symbolic view.)

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: 1.5 ⋅ cos x + 0.3 ⋅ sin x .

This automatically changes the Fit type (S1FIT, etc.) in the Symbolic Setup view to User Defined.

Computed statistics

One-variable

Statistic	Definition
NΣ	Number of data points.
TOTΣ	Sum of data values (with their
	frequencies).

Statistics aplet 8-13