Statistics Dictionary

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Stemplot

A stemplot is used to display quantitative data, generally from small data sets (50 or fewer observations). The stemplot below shows IQ scores for 30 sixth graders.

Stems
150
140
130
120
110
100
90
80

Key: 110
Leaves
1


2 6
4 5 7 9
1 2 2 2 5 7 9 9
0 2 3 4 4 5 7 8 9 9
1 1 4 7 8

7 represents an IQ score of 117

In a stemplot, the entries on the left are called stems; and the entries on the right are called leaves. In the example above, the stems are tens (80 and 90) and hundreds (100 through 140). However, they could be other units - millions, thousands, ones, tenths, etc. In the example above, the stems and leaves are explicitly labeled for educational purposes. In the real world, however, stemplots usually do not include explicit labels for the stems and leaves.

Some stemplots include a key to help the user interpret the display correctly. The key in the stemplot above indicates that a stem of 110 with a leaf of 7 represents an IQ score of 117.

See also:   AP Statistics Tutorial: Stemplots (aka, Stem and Leaf Plot)