Education Technology

# Knowledge Base

## Solution 34497: Creating and Viewing a Residual List on the TI-84 Plus C Silver Edition.

### How do I view a residual list on a TI-84 Plus C Silver Edition?

When the TI-84 Plus C Silver Edition calculates a regression, there will be a difference between the values of f(x) as calculated and the value as determined by the "best fitting" line. This difference is called a residual.

When regressions are calculated, these residuals are automatically stored within a list called RESID. To view the RESID list, place it into a list in the List editor.

For example:

Caculate a linear regression for the following values:

L1: {1, 2, 3, 4, 5, 6}
L2: {2, 4, 6, 8, 9, 12}

1) Press [STAT] [1].
2) Press [Up Arrow] until the cursor is on the top line, highlighting L1.
3) Press [CLEAR] [ENTER].
4) Press [Down Arrow] [1] [ENTER] [2] [ENTER] [3] [ENTER] [4] [ENTER] [5] [ENTER] [6] [ENTER].
5) Press [Right Arrow] [Up Arrow] until the cursor is on the top line, highlighting L2.
6) Press [CLEAR] [ENTER].
7) Press [Down Arrow] [2] [ENTER] [4] [ENTER] [6] [ENTER] [8] [ENTER] [9] [ENTER] [12] [ENTER].

8) Press [2ND] [QUIT].
9) Press [STAT] [Right Arrow] to highlight CALC.
10) Press 4:LinReg (ax+b).
11) Ensure Xlist is set to L1, Ylist is set to L2, and Store RegEQ is set to Y1 by selecting [VARS] [Right Arrow] [1] [1] [ENTER].

12) Press [ENTER] on Calculate.
13) The linear regression will now be calculated and stored to Y1.

To view the RESID list:

1) Press [STAT] [1].
2) Press [Right Arrow] until you get to L6.
3) Press [Up Arrow] [Right Arrow].
4) Press [2nd] [LIST] to open the List Editor.
5) Press 7: RESID.
6) Press [ENTER].

To graph the linear regression along with the statistical data:

1) Press [2nd] [STAT PLOT] [1].
2) Use the settings listed in the image below. To change the menu settings use the arrow keys to navigate the options and press the [Enter] key to select an option.

3) Press [GRAPH].
4) Press [ZOOM] [9].

Please see the TI-84 Plus C Silver Edition guidebook for additional information.