What is a stem and leaf diagram?

A stem and leaf diagram is a visual representation of the distribution of your data, similar to a histogram. The advantage is that a stem and leaf diagram is very quick and easy to put together as it uses only the numbers of your dataset.

Let's say you had the following dataset:

32 4 36 4 16 23 30 45 31 6 31 29

which is equivalent to:

32 04 36 04 16 23 30 45 31 06 31 29

or looking at it another way:

3|2 0|4 3|6 0|4 1|6 2|3 3|0 4|5 3|1 0|6 3|1 2|9

I've just placed a "|" as a visual way of separating the tens from the units. The numbers before the "|" (i.e. 0,1,2,3,4) will be our "stems". Each corresponding number after the "|" will form the "leaves" and be placed next to the appropriate stem.

When you put it together the stem and leaf diagram looks like this:

0|446

1|6

2|39

3|26011

4|5

The most appropriate stem and leaves depend on the particular dataset. For example, the stem and leaf diagram of the following set of numbers:

100.5 100.4 99.9 100.5 101.4 100.1 100.5 101.9

Would look like this:

099|9

100|54515

101|49