What is important to know about Stem & leaf diagrams?

Stems go on the left, leaves on the right.

What is important to know about Stem & leaf diagrams?

Leaves should be listed in order smallest to largest.

What is important to know about Stem & leaf diagrams?

Always include a key, e.g. "2 | 4 means 24".

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Statistics & Probability · Foundation

Stem & leaf diagrams

A stem-and-leaf diagram organises a data set by splitting each value into a "stem" (the leading digits) and a "leaf" (the final digit). It keeps all the original data while making the distribution clear.

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Key facts to remember

1Stems go on the left, leaves on the right.
2Leaves should be listed in order smallest to largest.
3Always include a key, e.g. "2 | 4 means 24".
4The median is easy to find by counting in from the ends.
5Back-to-back stem-and-leaf diagrams compare two data sets on the same stems.

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Worked examples

Example 1

Draw a stem-and-leaf diagram for: 22, 31, 18, 25, 27, 19, 34, 23, 28.

Working

Stems: 1, 2, 3.
Stem 1 → leaves 8, 9
Stem 2 → leaves 2, 3, 5, 7, 8
Stem 3 → leaves 1, 4
Add key: 2 | 5 means 25.

AnswerRows: 1 | 8 9 ; 2 | 2 3 5 7 8 ; 3 | 1 4. Key: 2 | 5 = 25.

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Common mistakes

✗Forgetting the key — you lose a mark.

✗Leaves out of order.

✗Using two-digit leaves.

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Exam tips

✓Always add a key.

✓Order the leaves smallest to largest.

✓To find the median, count in from both ends simultaneously.

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