## How to Find a Five Number Summary and Create a BoxPlot on the TI-89 Graphing Calculator

A five number summary in statistics is made up of a Minimum, Median, Maximum and Q1/Q3. Q1 and Q3 help you to find the interquartile range: an important factor in looking at the spread of data. When you create a box plot with whiskers on the TI-89, the TI-89 will automatically calculate the five number summary for you, saving you time and effort.

Sample problem: Create a boxplot and find the five number summary for the following data: 200, 350, 300, 350, and 400.

Step 1: Create a new folder called “Box.” From the screen, press and scroll down to NewFold (option B). Press .

Step 2: Enter to spell B O X and press .

Step 3: Press , then scroll down to Stats/List Editor. Press twice.

Step 4: Press the down arrow key to get to the first line of the list. Enter your data into list1. Follow each entry with a comma: 200, 350, 300, 350, 400.

Step 5: Press , to enter Plot Setup.

Step 6: Press , right arrow, and to select mod box plot.
Step 7: Arrow down to Mark and select box.

Step 8: Arrow down and enter B O X in the x box. to spell B O X. Press .

Step 9: Read the boxplot. Press and use the left and right cursors to find Min(200), Q1(250), Med(325), Q3(400), and Max(500).

Tip: if you want to change the folder back to MAIN, press , scroll down to Current Folder. Press right key, then press .
TipIf you get the error message undefined variable, it can be a frustrating process to try and solve the problem. Clearing the memory *may* help, but an easier way to get the box plot to graph is to enter the data into “list 1″ in the List Editor and then type “list 1″ as your “x” when defining the box plot.

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## 9 Responses to “How to Find a Five Number Summary and Create a BoxPlot on the TI-89 Graphing Calculator”

1. ### Anthony Prato said:

Sep 15, 10 at 7:05 pm

Upon completing step 8, I press enter and I return to the plots list. My “box” plot is checked as if ready to graph. After step 8, I pressed the green button and F3 to enter “graph”, because I wanted to graph the box plot. The calculator takes me to the graph screen, but then says “ERROR” undefined variable. I followed all previous instructions. I an using a TI-89 Titanium.

2. ### Stephanie said:

Sep 16, 10 at 10:23 am

Anthony,
Try resetting the variable memory.
• Press [2nd] [6] (MEM) [F1] [ENTER]
• Select 2:Default
• Press [ENTER] and Defaults Set is displayed
• Press [ENTER]
Stephanie

3. ### Shane said:

Sep 13, 11 at 7:32 pm

I know this is late, but for anyone else stumbling upon this site with the same question as Anthony, here it is. The Titanium is slightly different. Instead of pressing f3 to graph, you have to go into y editor, which is f1. From there you can use the graphing function. Go to zoomData to fit the screen and there you have it.

4. ### Orchid said:

Sep 25, 11 at 11:19 am

I encountered the same screen and I also followed all the steps. It did not work.

Thanks.

5. ### Scott said:

Sep 25, 11 at 11:08 pm

I get the same error message even after following Stephanie’s reply on a Ti-89 Titanium. Anyone else?

6. ### Stephanie said:

Sep 27, 11 at 4:51 pm

Thanks, Shane :)

7. ### Andrew said:

Sep 12, 12 at 8:56 pm

Step 4 confuses me because I have the TI-89 Titanium and you can’t put commas after when entering it into the list L1. So I have just tried putting them in normally and the Y Editor step confused me? Where do I go from there?

8. ### Andale said:

Sep 15, 12 at 11:52 am

Hi, Andrew,
You don’t enter the commas. Just type the number, press “Enter” to get to the next line and then type the next number.
Regards,
Stephanie

9. ### TI 89 for StatisticsTopic Index | said:

Mar 05, 13 at 7:36 am

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