## Linear Regression

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

Press
and use
to select CALC. Press
This yields an equation of the form y = ax + b.

The linear regression option can also be obtained by pressing .
This yields an equation of the form y = a + bx.

The resulting equations are equivalent, y = 0.24x + 1.14 and y = 1.14
+ 0.24x. The TI-82 calculates the correlation coefficient, r. In this case,
r is about 0.91. 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-82 stores the regression equation. The equation can be graphed
and is transfered to
without typing the equation as follows. Press
and use
to select EQ.

Press
to view the regression equation and press .
The equation is now entered in .
Press .
The data points can also be viewed. Access STAT PLOTS by pressing
to turn the plots on. Press .

**Note:** The resulting linear equation is an exact fit if two nonvertical data
points are entered.
The TI-82 calculates the correlation coefficient r.