When carrying out an investigation, you will need to collect and record data from which you can draw conclusions. Learn about different ways of collecting, recording, organising and interpreting data.

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 stem and leaf diagram is formed by splitting the numbers into two parts - in this case, tens and units.
- The
**tens form the 'stem'**and the**units form the 'leaves'**. - This information is given in the key.

The numbers are usually ordered, so the row:

shows the numbers , , , , and in order.

- Question
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.