How to Construct Histograms on the TI-84 Plus

You can use the TI-84 Plus to create histograms. The most common plots used to graph one-variable data are histograms and box plots. In a histogram, the data is grouped into classes of equal size; a bar in the histogram represents one class. The height of the bar represents the quantity of data contained in that class.

To construct a histogram of your data, follow these steps:

1. Store your data in the calculator.

   Your data does not have to appear in the Stat List editor to plot it, but it does have to be in the memory of the calculator.

2. Turn off any Stat Plots or functions in the Y= editor that you don’t want to be graphed along with your histogram.

   To do so, press [Y=] to access the Y= editor. The calculator graphs any highlighted Plots in the first line of this editor. To remove the highlight from a Plot so that it won’t be graphed, use the

   

   keys to place the cursor on the on the Plot and then press [ENTER] to toggle the Plot between highlighted and not highlighted.

   The calculator graphs only those functions in the Y= editor defined by a highlighted equal sign. To remove the highlight from an equal sign, use the

   

   keys to place the cursor on the equal sign in the definition of the function, and then press [ENTER] to toggle the equal sign between highlighted and not highlighted.

3. Press [2nd][Y=] to access the Stat Plots menu and enter the number (1, 2, or 3) of the plot you want to define.

   The first picture shows this process, where Plot1 is used to plot the data.

   

4. Highlight On or Off.

   If On is highlighted, the calculator plots your data. If you want your data to be plotted at a later time, highlight Off. To highlight an option, use the

   

   keys to place the cursor on the option, and then press [ENTER].

5. Press

   

   Use

   

   to place the cursor on the type of plot you want to create, and then press [ENTER] to highlight it.

   Select “ to construct a histogram.

6. Press

   

   enter the name of your data list (Xlist), and press [ENTER].

   If your data is stored in one of the default lists L₁ through L₆, press [2nd], key in the number of the list, and then press [ENTER]. For example, press [2nd][1] if your data is stored in L₁.

   If your data is stored in a user-named list, key in the name of the list and press [ENTER] when you’re finished. Notice that the calculator is already in Alpha mode, waiting for the first letter in the name of your list.

7. Enter the frequency of your data.

   If you entered your data without paying attention to duplicate data values, then the frequency is 1. On the other hand, if you did pay attention to duplicate data values, you most likely stored the frequency in another data list. If so, enter the name of that list the same way you entered the Xlist in Step 6.

8. Press [ZOOM][9] to plot your data using the ZoomStat command.

   ZoomStat finds an appropriate viewing window for plotting your data. The next step shows you how to redefine the class size in a histogram.

9. Press [WINDOW], set Xscl equal to the class size you desire, and then press [GRAPH].

   The class size (Xscl) must be

   

   If it isn’t, you get the ERR: STAT error message.

10. If necessary, adjust the settings in the Window editor.

    The data plotted here consists of test scores. For such data, you naturally want the class size (Xscl) to be 10. But when the histogram is graphed again using this class size (as in the first picture), the viewing window doesn’t accommodate the histogram. To correct this, adjust the settings in the Window editor. The second picture shows the result of adjusting these settings.