Print

Maths

Pie charts and frequency diagrams

Page:

# Drawing a frequency diagram for grouped data

Here is the data for the ages of customers shopping in the Bitesize CD store.

## Bitesize CD store 16th May 2008

Ages of customers in 1-hour period25, 29, 45, 19, 36, 17, 60, 51, 39, 24, 15, 13, 31, 18, 24, 32, 37, 27, 23, 53, 41, 34, 29, 28, 52, 17, 55, 47, 34, 28, 22, 20, 64, 39, 38, 33, 24, 16, 27, 19, 26, 27, 25, 32, 26, 48, 54, 35

We could show this data in a bar chart, but it would have a lot of bars! As ages are continuous data, we can group them together so that we have fewer categories.

This is the same set of data put into groups:

AgeNumber of people
11-209
21-3016
31-4012
41-504
51-606
61+1

We can now put the data into a pie chart or frequency diagram.

When choosing intervals for the data sets make sure that they do not overlap and that they include all the data.

For example you could use the above intervals to draw a frequency bar chart:

bar graph

Page:

Back to Statistics and probability index