# Knowledge Base

## Solution 10395: Calculating a Linear Regression Using the TI-85.

### How do I calculate a Linear Regression using the TI-85?

The following example will demonstrate how to perform a Linear Regression using the TI-85

Example:

xstat = {2, 3, 6}
ystat = {5, 11, 13}

Solution:

1) Clear the home screen then press [STAT] [F2] [F1] [ENTER] [ENTER]
2) The cursor will display after x1 =.
3) Enter the data after "x1 =" Press  [ENTER]  [ENTER]  [ENTER]   [ENTER]  [ENTER]  .
4) Press [2nd] [F1] [ENTER] [ENTER].
5) Press [F3] to display the results for a linear regression.

The calculator will display the form of the equation (y=a+bx) and then list the values for the two coefficients (a and b). It will also list a value for corr. This is the correlation coefficient, and it needs to be as close as possible to 1 to ensure a good fit. (1.0 is a perfect fit, and anything less is an approximation. For example, .999 would be an excellent fit.) The final value listed is the number of points that were analyzed to generate the equation.