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 Home screen, press F4 and scroll down to **NewFold** (option B). Press Enter.

**Step 2:** Enter 2nd Alpha ( – x to spell B O X and press Enter.

**Step 3:** Press Apps, then scroll down to **Stats/List Editor**. Press Enter 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 F2, 1 to enter **Plot Setup**.

**Step 6:** Press F1, right arrow, and 5 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. 2nd Alpha ( – x to spell B O X. Press Enter.

**Step 9:** Read the boxplot. Press F3 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 Mode, scroll down to **Current Folder**. Press right key, then press 1 Enter.

**Tip**If 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.

Lost your guidebook? You can download a new one from the TI website here.

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.

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

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.

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

Thanks.

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

Thanks, Shane :)

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?

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