EDEXCEL GCSE FOUNDATION MATHS - What is Stem and Leaf

Edexcel GCSE Foundation Maths: Stem and Leaf Diagrams

What is a Stem and Leaf Diagram?

A stem and leaf diagram is a way to organise data to show its distribution. It's particularly useful for displaying numerical data that falls within a specific range.

Stem and leaf diagrams are made up of two parts:

• Stem: The left-hand side of the diagram represents the tens digit of the data.
• Leaf: The right-hand side of the diagram represents the units digit of the data.

How to Construct a Stem and Leaf Diagram

Let's take an example:

Suppose we have the following set of data representing the ages of students in a class:

15, 18, 19, 20, 22, 24, 25, 28, 29, 30

1. Identify the stem: The stem will be the tens digit of the data, so we have stems of 1, 2, and 3.

2. Create a stem column: Write down the stems in ascending order:

1 2 3

1. Add the leaves: For each data point, write its units digit next to the corresponding stem.

1 | 5 8 9 2 | 0 2 4 5 8 9 3 | 0

1. Order the leaves: Arrange the leaves in ascending order for each stem.

1 | 5 8 9 2 | 0 2 4 5 8 9 3 | 0

Advantages of Stem and Leaf Diagrams

• Provides an organised visual representation of data.
• Preserves the original data values.
• Helps to identify the shape and spread of the data.

Key Points to Remember

• The stem represents the tens digit.
• The leaf represents the units digit.
• Leaves must be arranged in ascending order for each stem.
• Stem and leaf diagrams can be used for both grouped and ungrouped data.

Example:

Data: 12, 16, 18, 21, 23, 25, 28, 30, 32, 35

Stem and Leaf Diagram:

1 | 2 6 8
2 | 1 3 5 8
3 | 0 2 5

This diagram shows that the data is clustered around the 20s, with a few values in the teens and 30s.