A **histogram**, or frequency distribution, is a type of graph that has bars representing data. Each bar represents a certain amount of data. If you are asked to make a **frequency distribution chart**, you can draw a **histogram** by hand, or you can get the TI-89 to do the work for you. Once you have input the data into the TI-89 and graphed the histogram, the TI-89 will even count how many items are in each bar (or class).

Sample problem: Create a frequency distribution chart for the following new car costs: 12,500; 22,400; 14,300; 32,200; 21,500; 19,980; 15,001; 22,001; 32,036; 35,124; 29,001; 25,006; 27,001; and 18,500.

**Step 1:** Press Apps and scroll to the Stats/List Editor. Press Enter.

**Step 2:** Press F1 then 8 to clear the list editor of data.

**Step 3:** Enter “cars” as the name by pressing 2nd alpha ) = 2 3 alpha Enter.

**Step 4:** Enter your data:

1 2 5 0 0 Enter

2 2 4 0 0 Enter

1 4 3 0 0 Enter

3 2 2 0 0 Enter

2 1 5 0 0 Enter

1 9 9 8 0 Enter

1 5 0 0 1 Enter

2 2 0 0 1 Enter

3 2 0 3 6 Enter

3 5 1 2 4 Enter

2 9 0 0 1 Enter

2 5 0 0 6 Enter

2 7 0 0 1 Enter

1 8 5 0 0

**Step 5:** Press F2 Enter and F1 to go into Plot Setup (Define Plot).

**Step 6:** Press the right scroll arrow to bring up a menu for Plot Type. Press 4 for **Histogram**.

**Step 7:** Scroll down to “**x**” Press 2nd - to bring up **Var-Link**. Scroll down to “cars” and press Enter Enter.

**Step 8:**Scroll down to **Hist. Bucket Width** and enter 5 0 0 0 Enter. This is your class width.

**Step 9:** Press Enter F5.

**Step 10:** Press F3 for the trace function. Use the left and right scroll keys to move from one bar to another. (This will tell you how many items are in each class (n = x)).

**Tip #1**: If your graph doesn’t show (or only part of the graph shows), you may need to change the window. Press ♦ F2 to check your window settings. For the above graph, your settings should be approximately 10000 < x < 40000 and 0 < y < 8. Press F2 9 to return to the graph.

**Tip #2**: Make sure the alpha lock is turned on by checking for a little black box with “a” in it on the bottom left of your screen.

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