Stem and Leaf Plots

Sorting Data using the TI-83

You can sort any list of data you enter in the TI-83. This is particularly useful for creating Stem and Leaf Plots and find quartiles, deciles and percentiles. Here is an example to show you how this is done

Example: Create a Stem and Leaf Plot for the following data which represents ages of CEO's:

53	45	41	36	55
50	37	48	52	62
43	46	39	50	52
61	48	37	48	55
59	52	39	41	50

The TI-83 will not create the Stem and Leaf Plot for you completely, but it will allow you to sort the data which makes creating the chart by hand easy. Here is what to do:

1.Enter the data into a free list (use L1 if it is available). Recall that you do this by hitting STAT, then 1 for Edit and clear L1 if necessary. After you have entered the data into L1 the screen should look like this:

2. Now hit 2nd MODE for quit to get to the homescreen. Now hit STAT to get this screen:

3. Now select 2 to get SortA( which stands for Sort Ascending). Your screen will look like this:

4. Enter the list you wish to sort in this case L1 (hit 2nd 1). Your screen looks like this:

5. Now hit enter, the screen will say done. Hit Stat then edit to get back to the editor. Your data should be sorted. Here is what the screen should look like:

Now we can construct the Stem and Leaf easily by just reading off the values. Here is the answer:

Ages of CEO

Stem	Leaf
3 3 4 4 5 5 6	67799 1135 6888 00222355 9 12

We can also use the Sorted Data to find quartiles, deciles and percentiles easily. Suppose with this data we wish to find and . Recall that Q1 is the 25th percentile. Since there are 25 pieces of data in this dataset, you should do the following calculation:

0.25*25=6.25. Round up to 7. Use the sorted list to find the 7th value which is 41. This is Q1

For P45, you do a similar calculation:

0.45*25=11.25. Round up to 12. Use the sorted list to find the 12th value, which is 48. This is P45

For D7, another very similar calculation:

0.70*25=17.5. Round up to 18. Use the sorted list to find the 18th value, which is 52. This is D7

Recall that if the calculation results in a whole number you find the average between the two values (see p. 88)

If all you need is quartiles and the median - you should probably use 1 Var Stats on the STAT CALC menu, it gives you these values automatically.

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