Split each number into a 'stem' (the big part) and a 'leaf' (the last digit). Line them up and you get a histogram — except you can still read every original number off it.
A stem-and-leaf plot organises numbers by splitting each into a stem (leading digits) and a leaf (final digit). The leaves line up beside their stems, forming a sideways histogram that keeps the actual data.
Quick hand analysis of test scores, ages, measurements — you get the shape *and* can recover the exact values, unlike a histogram.
Stem | Leaf: 3 | 2 5 7 4 | 0 1 1 8 5 | 3. How many data values are there, and what's the largest?
Building one
- Stem = all but the last digit (e.g., 47 → stem 4).
- Leaf = the last digit (47 → leaf 7).
- List stems vertically, write each leaf beside its stem in order.
- Add a key: '4 | 7 means 47'.
Put these in a stem-leaf plot: 23, 25, 31, 31, 38, 42.
Find the median from a stem-leaf plot of 9 values.
The median is the 5th value. Count leaves from the top: when you reach the 5th leaf, its stem+leaf is the median. No need to rewrite the data.
Leaves must be single digits and in order. Writing '12' as a leaf, or leaving leaves unsorted, defeats the purpose — you can't read the shape.
Back-to-back stem-leaf plots (leaves on both sides of one stem column) let you compare two datasets at a glance — like two histograms sharing an axis.
- Each value splits into stem (leading digits) + leaf (last digit).
- Acts like a histogram but preserves the original data.
- Always include a key; keep leaves single-digit and sorted.