How to Plot Two-Variable Data on the TI-84 Plus

You can use the TI-84 to construct scatter plots and xy-line plots. The most common plots used to graph two-variable data sets are the scatter plot and the xy-line plot.

The scatter plot plots the points (x, y) where x is a value from one data list (Xlist) and y is the corresponding value from the other data list (Ylist). The xy-line plot is simply a scatter plot with consecutive points joined by a straight line.

To construct a scatter plot or an xy-line plot, 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.

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.

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 name of your Ylist and press [ENTER].

8. Choose the type of mark used to plot points.

   You have three choices: a small square, a small plus sign, or a dot. To select one, use

   

   to place the cursor on the mark and press [ENTER].

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

   ZoomStat finds an appropriate viewing window for plotting your data.