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A stem-and-leaf plot is a visual representation of numerical data that displays the frequency of values in a dataset. It consists of a vertical line (the “stem”) with numbers on one side and horizontal lines (the “leaves”) with the corresponding values. This type of plot can be used to quickly identify the distribution of a dataset, including the range, median, and outliers. For example, a stem-and-leaf plot can be used to show the grades of students in a class, the temperatures recorded in a week, or the ages of participants in a survey. It is a useful tool for organizing and understanding numerical data.
A stem-and-leaf plot displays data by splitting up each value in a dataset into a “stem” and a “leaf.”
This tutorial explains how to create and interpret stem-and-leaf plots.
How to Make a Stem-and-leaf Plot
The following two examples illustrate how to create a stem-and-leaf plot from scratch for a given dataset.
Example 1
Suppose we have the following dataset:
12, 14, 18, 22, 22, 23, 25, 25, 28, 45, 47, 48
Here is what the stem and leaf plot looks like:
1 | 2 4 8
2 | 2 2 3 5 5 8
3 |
4 | 5 7 8
And here’s how to make it:
Step 1: split each value in the dataset into a “stem” and a “leaf.”
The “stem” of each value is the first digit:
12, 14, 18, 22, 22, 23, 25, 25, 28, 45, 47, 48
The “leaf” of each value is the second digit:
12, 14, 18, 22, 22, 23, 25, 25, 28, 45, 47, 48
Step 2: To make the plot, place the “stems” along the vertical axis and the “leaves” along the horizontal axis:
1 | 2 4 8
2 | 2 2 3 5 5 8
3 |
4 | 5 7 8
Suppose we have the following dataset:
134, 156, 158, 159, 160, 162, 164
Here is what the stem and leaf plot looks like:
13 | 4
14 |
15 | 6 8 9
16 | 0 2 4
And here’s how to make it:
Step 1: split each value in the dataset into a “stem” and a “leaf.”
In this case, since the values in this dataset have three digits, the “stem” of each value is the first two digits:
134, 156, 158, 159, 160, 162, 164
The “leaf” of each value is the last digit:
134, 156, 158, 159, 160, 162, 164
Step 2: To make the plot, place the “stems” along the vertical axis and the “leaves” along the horizontal axis:
13 | 4
14 |
15 | 6 8 9
16 | 0 2 4
How to Interpret a stem-and-leaf plot
Suppose we have the following stem and leaf plot that shows the number of ice cream cones that Marie sold at her ice cream shop during each of the past 14 days:
7 | 3 3 3 7 9
8 | 4 5 8 8
9 | 1 2 5 8 9
Question: What is the most cones that Marie sold on any given day?
Answer: 99 cones
7 | 3 3 3 7 9
8 | 4 5 8 8
9 | 1 2 5 8 9
Question: During how many days did Marie sell more than 80 cones?
Answer: nine days
7 | 3 3 3 7 9
8 | 4 5 8 8
9 | 1 2 5 8 9
(during these nine days, she sold 84, 85, 88, 88, 91, 92, 95, 98, and 99 cones)
Additional Resources
Stem and Leaf Plot Generator
An Introduction to Back to Back Stem-and-Leaf Plots
How to Create a Stem-and-Leaf Plot in Excel
How to Create a Stem-and-Leaf Plot in Python