stem and leaf diagram

In statistics, a means of representing data using numbers with just two significant figures. The stem is formed by the first digit and the leaf the second. The stem digits are laid out vertically in order, and the leaf digits arranged next to them horizontally. Leaf digits with the same stem number share a row and the leaves are arranged in ascending order from the stem; all leaf digits in a set of data are shown. Numbers should be rounded if necessary. The leaf can represent any chosen unit of measurement for the diagram, such as tens or hundreds, and so on. The unit of measurement being used must always be stated.

For example, a stem and leaf diagram for the numbers 39 42 46 32 54 41 would be:

which is then rearranged to give:

where 3 | 2 9 represents 32 and 39. The unit of measurement used can be shown as ‘3 | 2 = 32’ or ‘unit = 1’.

If the same number is repeated in a set of data, the leaf digit must be shown the equivalent number of times against its stem.

When single units are included, the stem digit 0 is used. For example, 8 is shown as 0 | 8, while 18 is 1 | 8.

If the numbers have more than two significant figures, a suitable unit of measurement must be chosen for the diagram and the numbers rounded off if necessary. For example, in a set of numbers ranging between 10 and 900, each leaf unit will represent 10. The number 23 is rounded to 20 as 0 | 2; 370 is 3 | 7; and 838 rounded as 8 | 4.