Stem and leaf diagrams
A stem and leaf diagram is one way of grouping data into classes and showing the shape of the data.
Example
A maths test is marked out of \({50}\). The marks for the class are shown below:
This is all the information that you require, but it is difficult to interpret. For example:
- Is it easy to tell whether more children got marks in the \({20}\)s than the \({30}\)s?
- Can you tell at a glance what the highest mark was?
- Can you see whether more than one person achieved the same result?
One way to represent the data so that you can answer these questions at a glance is in a stem and leaf diagram. This diagram shows the same results as the example above:
The numbers are usually ordered like this:
So this row shows the numbers \({21}\), \({23}\), \({24}\), \({24}\), \({25}\) and \({27}\) in order.
Use the stem and leaf diagram above to answer the following questions.
Question
How many children scored \({36}\)?
You can work this out by looking at the \({3}\) column in the tens:
Therefore \({2}\) children score \({36}\).
Question
What was the most common score?
You can work this out from the stem and leaf diagram below:
Therefore \({17}\) is the most common score.