Notes

Key points:
A pie chart is a type of graph used to show proportions in a sample of data. A pie chart resembles a circle which has been split into sectors.
The angle of each sector is representative of the proportions of the whole data sample.
If the sectors are coloured, a key should be included to explain what each colour represents
The proportions in a pie chart may be represented as a percentage.
When drawing a pie chart, a protractor will be used to draw the angles accurately. Being familiar with how to use a protractor will be helpful.

Creating a pie chart:

-To produce a pie chart, data is required. The data often comes in the form of a table.
-To create a pie chart, the size of the angles needed must be calculated.

1)Add the total frequency in the table.
2)Divided 360° by the total frequency.
3)Multiply each frequency by this value. These are the angles for each sector.
4)Construct a circle and draw a vertical line from the top to the centre.
5)In a clockwise direction, use a protractor to plot each angle in turn.
6)Label each sector or use a key to colour code each.
7)Give your pie chart a title.

Interpreting a pie chart:

It is possible to interpret a pie chart by looking at the proportions of the sectors.
The angles can be used to work out what proportion of the whole population a pie chart sector represents. These fractions would be out of 360°, the number of degrees in a full turn.
A pie chart may include the percentages of what each sector represents. These can also be used to work out proportions of the whole population.