In most TI-89 calculators, you must load a new operating system first and then the APPS statistics program. You can either go to your instructor OR you can go to the TI-89 site to get the operating system and the APPS statistics program. You must go to the TI-89 site to get the Guidebook. It has all the instructions for running the statistics program.

To go to the TI-89 site, click http://education.ti.com to get to the TI-89 link. Then choose "apps" and "Handheld Software Application." From this page, you can download the operating system (version 2.05) and statistics program (Statistics with List Editor - this page will have both the operating system and the program).

You must then load the Advanced Mathematics Software Operating System and the Statistics with List Editor from your computer to the TI-89 calculator (unless your instructor has loaded them directly into your calculator). For that, you will need the TI-GRAPH LINK™ software and the TI-GRAPH LINK™ Cable. TI sells them on their Web Site.

Back to Top

Getting Started

Create the folder “mystat” (for statistcs):

1. Press 2nd VAR-LINK. Press F1 Manage.
2. Press 5: Create Folder. Enter the name “mystat” and press Enter twice.

Make mystat your current folder:

1. Press MODE. Arrow down to Current Folder and arrow over and down to mystat.
2. Press Enter twice. You should see the name MYSTAT in the lower left corner.

Creating list names L1, L2, and L3:

1. Press APPS 1:Flashapps. Press Enter.
2. Arrow up into the name area of the lists and over until you reach a blank title area.
3. Press L (above the 4). Press alpha. Press 1. Press Enter.
4. Arrow up into the name area of the lists and over until you reach a blank title area.
5. Press L. Press alpha. Press 2. Press Enter.
6. Arrow up into the name area of the lists and over until you reach a blank title area.
7. Press L. Press alpha. Press 3. Press Enter.

Back to Top

Linear Regression

Given the data set: (3, 5), (6, 8), (9,7), (5, 20). The xlist is 3, 6, 9, 5 and the ylist is 5, 8, 7, 20.
Put the xlist into L1 and the ylist into L2.

Constructing a Scatter Plot

1. Make sure you are using Flashapps (Press APPS 1: Flashapps. Press Enter.)
2. SCATTERPLOT: After you are have entered your lists in L1 and L2, press F2.
3. Press 1: Plot Setup. Highlight Plot 1 and make sure there are no checks next to any other plots. If there are, arrow to the plot and press F4.
4. Then arrow back to Plot 1.
5. Press F1: Define. For Plot Type, press the right arrow and press 1: Scatter.
6. Arrow down, press the right arrow and press 1:Box.
7. Arrow down to x. Press alpha L1. Arrow down to y and press alpha L2.
8. Arrow down to "Use Freq and Categories?" and use the right arrow. Highlight NO and press Enter.
9. Press Enter again.
10. Press F5 Zoomdata. You should see the scatterplot. Press F3 to trace and the arrow keys to see the coordinates of the points.

Back to Top

Calculating the Regression Equation

1. Press APPS, 1: Flashapps, and Enter.
2. Press F4: Calc.
3. Press 3: Regressions.
4. Press 1: LinReg (ax+b). For x List, enter alpha L1. Arrow down. For y List, enter alpha L2.
5. For "Store RegEqn to:", arrow right and arrow down to y1(x) (or any one of the y's) and press Enter.
6. Press Enter. You should see a screen with a, b, r^2, and r on it. The regression is complete.
7. Write down the equation from the information and press Enter.
8. The linear regression is yhat = 11.2267 - .2133x

Back to Top

Drawing the Regression Line

1. Press the key with the green diamond on it (it is below the 2nd key) and press Y= (above the F1 key).
2. This is the Line of Best Fit.
3. Press the key with the green diamond on it and press GRAPH (above the F3 key). The line will be drawn.

Outliers

1. When you do Linear Regression, a list called "resid" is created automatically.
2. This list has the “y – yhat” values in it.
3. Go into Flashapps and into your lists.
4. Arrow to "resid" so you see it.
5. Then, arrow to the list name L3. Press F3.
6. Press 1: names. Arrow down to STATVARS. If it is not checked, press F4.
7. Then, arrow down to resid. Press Enter. Press ^2. Press Enter. L3 will have the (y - yhat)^2 values.
8. Press HOME and Press F1 8 to clear it.
9. Press 2nd MATH. Press 3: List. Press 6: Sum. Press alpha (L3).
10. Depending on how you have MODE Display Digits set, you should see approximately 137.1467. This is the SSE.
11. Calculate s. (You should be HOME.) Press clear.
12. Press the square root symbol and enter 137.1467/2. (You get the denominator by taking the number of data points and subtracting 2: 4 - 2 = 2.)
13. Press Enter. You should see 8.2809 (to 4 decimal places).
14. Press the times key and enter 1.9. Press Enter. You should see 15.7337.
15. Press clear. Press 2nd VAR-LINK.
16. Arrow down to resid (it is below STAT VARS). Press Enter. Press Enter again.
17. Arrow up to the list. Scroll through the list using the arrow keys.
18. Compare 15.7337 to the absolute values of the numbers in the list. If any absolute value is greater than or equal to15.7337, then the corresponding point is an outlier.
19. Absolute values of the numbers in the list are approximately 5.59, 1.95, 2.31, 9.84.
20. None of them are greater than or equal to 15.7337.
21. Therefore, for this data set, no point is an outlier.

Back to Top