Stem and Leaf Plot Examples- Visual Guide
What Is a Stem and Leaf Plot?
A stem and leaf plot is a data visualization tool that shows the shape of a dataset while keeping the original values intact. Unlike bar charts or histograms that hide individual numbers, stem and leaf plots display every single data point.
The structure is simple. Each number splits into two parts:
- Stem — the leading digit(s)
- Leaf — the trailing digit(s)
Think of it like organizing your closet. The stems are your hanging clothes, and the leaves are the items folded inside each section. Everything has its place, and you can see everything at once.
How to Read a Stem and Leaf Plot
Reading one of these plots takes about 30 seconds once you know the trick. Here's a quick example using test scores:
| Stem | Leaves |
|---|---|
| 6 | 8 9 |
| 7 | 2 4 7 9 |
| 8 | 1 3 5 5 8 |
| 9 | 0 2 4 6 7 9 |
This plot shows scores from the 60s through the 90s. The stem "7" with leaves "2 4 7 9" represents the values 72, 74, 77, and 79.
The rule: Stem + Leaf = Actual Value. Always.
Stem and Leaf Plot Examples by Data Type
Example 1: Student Test Scores
Let's say you have these 15 scores: 78, 82, 91, 65, 88, 73, 95, 81, 69, 84, 77, 92, 86, 70, 89
| Stem | Leaves |
|---|---|
| 6 | 5 9 |
| 7 | 0 3 7 8 |
| 8 | 1 2 4 6 8 9 |
| 9 | 1 2 5 |
Reading this: You have 2 scores in the 60s, 4 in the 70s, 6 in the 80s, and 3 in the 90s. The distribution skews toward the higher end. That's useful information in under 5 seconds.
Example 2: Daily Temperature Readings
Temperature data often works well with stem and leaf plots because you can use decimals as leaves.
| Stem | Leaves |
|---|---|
| 72 | 3 5 8 |
| 73 | 1 4 6 9 |
| 74 | 0 2 7 |
| 75 | 3 5 |
Stem = 72, Leaves = 3, 5, 8 means temperatures of 72.3, 72.5, and 72.8 degrees. The stem can be two digits when your data requires it.
Example 3: Ages of Survey Respondents
For clustered data like ages, you might want to use split stems to show more detail.
| Stem | Leaves |
|---|---|
| 1 | 8 9 |
| 2 | 1 4 7 |
| 3 | 2 5 8 |
| 4 | 0 3 6 9 |
| 5 | 1 2 4 5 |
This shows ages 18-19, 21, 24, 27, 32, 35, 38, 40, 43, 46, 49, 51, 52, 54, and 55. You can see the data clusters around the 40s and 50s.
Example 4: Back-to-Back Stem Plot for Comparison
When you need to compare two datasets, use a back-to-back stem plot. Here's class A vs class B scores:
| Class A | Stem | Class B |
|---|---|---|
| 5 | 6 8 | |
| 9 7 4 | 6 | 2 3 5 |
| 8 6 5 3 | 7 | 1 4 7 |
| 9 7 5 2 | 8 | 3 6 |
Class A has more high scores (80s), Class B has more mid-range scores. The comparison is instant.
When to Use a Stem and Leaf Plot
These plots work well when:
- Your dataset has between 15 and 150 data points
- You want to see the distribution shape without losing detail
- You need to identify clusters, gaps, or outliers
- You're comparing two related datasets
They don't work well for:
- Large datasets (over 200 points) — too cluttered
- Categorical data — use bar charts instead
- When you only need the big picture — histograms are cleaner
Stem and Leaf Plot vs Other Tools
| Feature | Stem and Leaf | Histogram | Box Plot |
|---|---|---|---|
| Shows individual values | Yes | No | No |
| Easy to construct by hand | Yes | Yes | No |
| Good for small datasets | Yes | Okay | No |
| Shows exact median | Yes (count leaves) | No | Yes |
| Works for large datasets | No | Yes | Yes |
Common Mistakes to Avoid
- Using too many digits as stems — If your data ranges from 1 to 1000, you need to round first or use intervals
- Forgetting to sort leaves — Leaves should always be in ascending order within each stem
- Mismatched place values — If stems are tens, leaves must be ones. Don't mix 2-digit leaves with 1-digit stems
- Leaves without spaces — "125" looks like one value. Write "1 2 5" instead
How to Create a Stem and Leaf Plot
Here's the step-by-step process using real data:
Data: Monthly rainfall in inches — 3.2, 4.1, 2.8, 5.6, 4.3, 3.9, 6.2, 4.8, 3.5, 5.1, 4.2, 3.7
Step 1: Round if needed. Round to one decimal place since we're working with tenths.
Step 2: Identify the stems. The whole number part becomes the stem. So stems are 2, 3, 4, 5, 6.
Step 3: Write leaves in order. The decimal part becomes the leaf.
| Stem | Leaves |
|---|---|
| 2 | 8 |
| 3 | 2 5 7 9 |
| 4 | 1 2 3 8 |
| 5 | 1 6 |
| 6 | 2 |
Step 4: Sort each row. The leaves 2, 5, 7, 9 are already in order. Leaves 1, 2, 3, 8 are in order.
Step 5: Add a key. Write "3 | 2 represents 3.2 inches" somewhere on your plot.
Split Stems: When Standard Plots Fall Short
Sometimes standard stems don't show enough detail. If your data has too many values in one stem, split it.
Instead of one row for "8", use two rows:
- 8 | 0-4
- 8 | 5-9
This doubles your resolution. It's especially useful when data clusters tightly in one area.
What You Can Learn at a Glance
A well-made stem and leaf plot tells you:
- Mode — the stem with the most leaves
- Range — lowest stem/leaf to highest stem/leaf
- Distribution shape — symmetric, skewed left, skewed right
- Gaps and outliers — missing stems or lone leaves at the ends
- Clusters — where data concentrates
You get all that without calculating anything. Just look.
The Bottom Line
Stem and leaf plots are old-school, but they work. They're perfect for exploratory data analysis when you need detail without a computer. If you're grading papers, tracking measurements, or comparing small groups, this is your tool.
Print out your data, draw a vertical line, and start splitting numbers. That's it.