1) Click on the STAT button of your TI 84
2) Select "Edit".


3) Scroll RIGHT to "CALC" and press the enter buton
4) Scroll down to "LinReg(ax +b) " 

5) Then press L1, "," and , "L2" ( to get 'l1' press '2nd' then the '1' key) and ","  Graphing calculator screen should now show:

6) The next step will create the graph. Press "Vars" scroll to 'YVars' and select "Function". Choose Y1 (you are now storing this linear regression in the y1 graph so that you can graph the actual regression. 7)Press enter, go to 'graph' to see the graph 