# TI-84 Calculator

Instructions on Using the Graphing Calculator for Linear Regression Models:

1. First, you need to enter the data.  Begin by pressing the [STAT] key.

2. Press [1] or [ENTER] for Edit.

(If you see data on the screen, use the up arrow to go up to the top where the list names occur, press the [CLEAR] key and go back down to the list.)

3. Now enter the values give in L1 and L2.  L1 is the Right foot (cm) data and L2 is the Height (cm) data.  Press [ENTER] or the down toggle key after each value is inputted.

4. Use the right toggle key, to enter the L2 when the L1 has been completed.  Make sure the same amount of values have been entered for L1 and L2.

5. When all the data has been entered, press the [2nd] key and then the [STATPLOT] key.  The [STATPLOT] key is above the [Y=] key.

6. Press [ENTER] to begin setting up the parameters of your scatter plot.

The following should be highlighted:

On

Type: First graph should be highlighted

Xlist: L1

Ylist: L2

The first Mark should be highlighted.

7. Press [ZOOM]  [9] to show the scatter plot.

8. Now the calculator can find the equation of the line of best fit.  Press the [STAT] key again, but this time use the right arrow to move over to CALC.

8. Since we want a linear regression, we press [4] or scroll down to 4: LinReg (ax + b) and press [ENTER].  The calculator now prints that statement on the home screen.

9.  After the statement LinReg (ax + b), press [2nd] [L1] [,] [2nd] [L2] [,] [VARS].  Then right toggle to Y-VARS and press [ENTER] for 1: Function.  Press [ENTER] for  Y1, which tells the calculator to use List 1 and List 2 and put the regression equation in the Y = screen, spot Y1.

10. Press [ENTER] to determine the equation and the correlation coefficient.

11. Press [GRAPH] to view the line of best fit.

Note the following:

- The equation of a line is given as y = ax + b instead of y = mx + b where a represents the slope and b represents the y intercept.

-You can round your a and b values to the nearest hundredth and substitute them into the standard linear equation.

-The r indicates the correlation coefficient.

-If r, the correlation coefficient, does not appear on your screen, press [2nd] [CATALOG].  Scroll down to the D’s and press [ENTER] next to Diagnostic On.  The calculator will print DiagnosticOn on the home screen; hit [ENTER] again and the calculator will print Done.  Then re-enter the linear regression command and now you will see the correlation coefficient.