Organising data & statistical charts · Ages 12–13
Stem-and-leaf diagrams
One leaf, one value; the leaves run in order.
How to do it
Method
One leaf, one value; the leaves run in order
4 | 2 5 7 is 42, 45, 47
Another way
Write the values out
5 | 0 3 → 50, 53
In full
A stem-and-leaf diagram splits each value into a stem and a leaf: for a two-digit number the tens digit is the stem and the units digit the leaf, written right of the line, one stem's leaves in a row from smallest to largest. The key under it (say 4 | 5 = 45) says how to read it. Reading it: each leaf is one value, so counting leaves counts the data; the least value is the first leaf in the first row, the greatest the last leaf in the last row. As the leaves are in order, 'the 3rd smallest' is counted from the first row, and '50 or more' counts the leaves in stem 5's row and after. You can also write each value out in full and count, but counting on the diagram is quicker. A stem-and-leaf diagram keeps every value exactly.
Worked examples
Have a go first, then open each one for the answer and the working.
Example 1
The stem-and-leaf diagram shows a team's scores. What is the highest score?
Show the answer and working
Answer: 51
The highest is the last leaf in the last row: 51.
Example 2
The stem-and-leaf diagram shows a team's scores. How many data are there?
Show the answer and working
Answer: 14
Each leaf is one value: count the leaves, 14 of them.
Example 3
The stem-and-leaf diagram shows a team's scores. Which of these scores is not in it?
- A. 40
- B. 48
- C. 51
- D. 45
Choose the right answer
Show the answer and working
Answer: D. 45
Split 45 into stem and leaf: that leaf isn't in that row, so it isn't among the diagram's 13 values.
Practice questions to try
Try these 5; the answers are at the end. For a whole worksheet, see VIP worksheets below.
1.The stem-and-leaf diagram shows a team's scores. What is the highest score?
Answer:
2.The stem-and-leaf diagram shows how many sit-ups each player of a team did in a minute. What is the fewest?
Answer:
3.The stem-and-leaf diagram shows a team's scores. Which of these scores is not in it?
- A. 28
- B. 27
- C. 41
- D. 33
Choose the right answer
Answer:
4.The stem-and-leaf diagram shows a team's scores. How many scored 40 or more?
Answer:
5.The stem-and-leaf diagram shows a team's scores. What is the 4th highest score?
Answer:
All the answers
- 1. 62
- 2. 39
- 3. A. 28
- 4. 7
- 5. 50
VIP practice notes and papers
Aimed at tests and exams: questions on this topic, new every time, to print or save as a PDF.
- Practice notes: The key point, worked examples step by step, then questions of the same kind to follow, hints fading
- Practice paper: Set out in parts like a school paper, marked, with answers and full working
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