A stem and leaf diagram displays numerical data in an ordered way, making it easy to find the median, mode, and range while preserving all the original data values.
12 4 7 9
20 3 5 5 8
31 4 6
42 8
Key: 2 | 3 means 23
n = 14 values · Median at position (14+1)/2 = 7.5 → average of 7th and 8th values
7th = 25, 8th = 28 → Median = 26.5
📖 Learn
How to Draw a Stem and Leaf Diagram
Steps:
Decide on the stems (usually the tens digits)
Write the stems in a column, smallest to largest
For each data value, write the leaf (units digit) in the appropriate row
Order the leaves in each row (smallest to largest)
Always include a key: e.g. "3 | 7 means 37"
💡 Each leaf represents one data value. The diagram preserves all original data.
Reading Statistics from a Stem and Leaf
n = total number of leaves Minimum = first leaf on the first stem Maximum = last leaf on the last stem Mode = most repeated leaf (on same stem) Median = middle value (position (n+1)/2 when all values listed in order) Quartiles: Q1 at position (n+1)/4, Q3 at position 3(n+1)/4
Back-to-Back Stem and Leaf
Used to compare two datasets. The stems go in the middle, with one dataset's leaves on the left and the other's on the right.
Boys | Stem | Girls
9 7 412 5 8
8 5 2 021 3 6
6 3 130 4 7
💡 For back-to-back: left side leaves are read from right to left (smallest nearest the stem).
✏️ Worked Examples
Example 1: Drawing a stem and leaf
Data: 34, 22, 41, 37, 28, 35, 44, 22, 30, 47
Stems: 2, 3, 4 (tens digits)
2 | 2 2 8 (leaves: 2,2,8)
3 | 0 4 5 7 (leaves: 0,4,5,7)
4 | 1 4 7 (leaves: 1,4,7)
Key: 3 | 4 means 34. n = 10
Example 2: Finding median and quartiles
From the diagram above (n=10): 22, 22, 28, 30, 34, 35, 37, 41, 44, 47
Median: average of 5th and 6th = (34+35)/2 = 34.5
Q1: median of lower half (22,22,28,30,34) = 28
Q3: median of upper half (35,37,41,44,47) = 41
IQR = Q3 − Q1 = 41 − 28 = 13
Example 3: Back-to-back — comparing datasets
Class A scores: 14,18,22,25,27,31,33. Class B scores: 12,19,23,26,29,30,35.
Class A median (n=7) = 4th value = 25
Class B median = 4th value = 26
"Class B has a slightly higher median (26 vs 25). Class A has lower range."
🎨 Visualizer
Stem and Leaf Builder
Enter comma-separated whole numbers (20–99 for 2-digit):