Fitting a curve to 2VAR data

In the Plot view, press ),7_. This draws a curve to fit the checked two-variable data set(s). See “To choose the fit” on page 8-11.

>3/27@

0(18_

),7_

>6<0%@

 

6+2:_

 

 

 

 

 

 

The expression in Fit2

 

 

 

shows that the

 

 

 

slope=1.98082191781 and

 

 

Correlation

the y-intercept=2.2657.

 

 

 

 

The correlation coefficient is stored in the CORR variable. It is

coefficient

a measure of fit to a linear curve only. Regardless of the Fit

 

model you have chosen, CORR relates to the linear model.

Relative Error

The relative error is stored in a variable named RELERR. The

 

relative error provides a measure of fit accuracy for all fits,

 

and it does depend on the Fit model you have chosen.

 

The relative error is a measure of the error between predicted

 

values and actual values based on the specified Fit. A smaller

 

number means a better fit.

H I N T

 

 

 

In order to access these variables after you plot a set of

 

statistics, you must press >180@ to access the numeric view

 

and then 67$76_ to display the correlation values. The values

 

are stored in the variables when you access the Symbolic

 

view.

 

 

 

 

Statistics aplet

8-17