## Linear Regression

_

The linear regression option finds the equation of a linear equation of
the form y = ax + b that best fits a set of data.
First, press
to
enter the data .

Press
to view the statistics calculation options.

Press .
Enter the columns to be used for the x and y entries, c1 and c2 in this case.

The regression equation can be automatically stored in the equation editor by selecting
the Stor RegEQ.

The resulting equation is y = 0.39x - 2.86. The TI-89 calculates the correlation
coefficient, r. In this case, r is about 0.51.
The value of r lies between -1 and 1, inclusive. It is a measure of how well the
regression equation fits the data.
A value of -1 or 1 indicates a perfect fit. The TI-89 also calculates the correlation
of determination, R^{2}.

**Note:** The resulting linear equation is an exact fit if two nonvertical data points
are entered.