A stem and leaf diagram is one way of grouping data into classes and showing the shape of the data.
A maths test is marked out of . 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 s than the s? Can you tell at a glance what the highest mark was, or 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, so the row:
shows the numbers , , , , and in order.
Using the stem and leaf diagram above, answer the following questions.
Q1. How many children scored ?
Q2. What was the most common score?
A1. You can work this out by looking at the column in the tens:
Therefore children score .
A2. You can work this out from the stem and leaf diagram below:
Therefore is the most common score.