figure 1
figure 2
figure 3
For this example we will use the following data on hours of
weekly TV viewing.
25, 66, 34, 30, 41, 35, 26, 38, 27, 31, 32, 30, 32, 15,
38, 20, 43, 5, 16, 21
Enter this data into a list on the calculator. (See
the handout: Entering Data and Histograms on the TI 83.)
Press the STAT key and the screen should look like figure 1. Use the blue arrow keys to highlight CALC. The screen should look like figure 2.
|
figure 1 |
figure 2 |
figure 3 |
Since "1:" is highlighted and that is the selection we want, you can press the ENTER key or the 1 key. This will cause the command to be displayed on the home screen looking like figure 3. If you entered the data in a list other than L1, be sure to indicate that list.
Pressing the ENTER key will cause the calculator to actually perform the command. The screen will look like figure 4.
The first line is the average or arithmetic mean. The second line is the sum of all the data items. The third line is the sum of the square of each data item. The fourth line is the sample standard deviation. The fifth line is the population standard deviation. The last line shows the number of items and has a down arrow at the beginning. The down arrow indicates that there is additional information. Use the blue down arrow key to scroll down to the bottom of the information. The result will look like figure 5. This screen shows the smallest data item, the first quartile, the median (or second quartile), the third quartile, and the largest data item.
figure 4 |
figure 5 |
A graphical presentation of the data contained in figure 5 is a Boxplot. Press the 2nd key followed by the Y= key which is the STAT PLOT function (figure 6). Press ENTER or 1 key to work with Plot1 (figure 7). Select the Type to be as shown in figure 8 and Xlist to be the list your data is in.
figure 6 |
figure 7 |
figure 8 |
Press ZOOM key and the screen will look like figure 9. Either use the blue arrow keys to move the cursor down to 9:ZoomStat (figure 10) and then press ENTER or simply press 9 key.
figure 9 |
figure 10 |
figure 11 |
The Boxplot will then be displayed (figure 11). This is the graphical presentation of the data in figure 5. To see this, press TRACE key and the screen will look like figure 12. This highlights the vertical bar indicating the median and shows the value at the bottom. Using the blue cursor keys to move left and right the other values may also be checked.
The Boxplot is a visual presentation of the 5 number summary (figure 5). The box portion of the plot identifies the middle 50% of the data and can be used to identify outliers. The calculator does this in a Modified Boxplot. Since the data is already in the calculator and the graphing window already set up, we simply press the 2nd key followed by the Y= key which is the STAT PLOT function and select the modified boxplot under Type (figure 13). Then press GRAPH to see the result with outliers identified by the small square (figure 14). Again the trace function can be used to obtain more information from the graph.
figure 12 |
figure 13 |
figure 14 |