1. Make sure your Plot 1 is ON. Select the Scatter Plots and the appropriate lists.
Go to: [2nd] "Stat Plot". [Enter].
2. Clear all functions in [Y=]
3. Input data in L1 and L2.
Go to [Stat] [Enter] to input data.
4. Graph data points.
Go to: [ZOOM] "9: ZoomSTat".
5. Choose a regression from the list in [Stat] "CALC".
Go to: [STAT] "CALC". Use the arrow keys to select the desired regression. [ENTER]. [2nd] L1, [2nd] L2, [VARS] "YVARS" [ENTER] [ENTER] . Then [ENTER] again.