Comparing discrete and continuous data

We can compare discrete and continuous data by looking at how water comes out of a tap.

A dripping tap shows discrete data, because each individual drop can be counted. The data collected will simply show the number of drops.

A gushing tap is an example of continuous data. It would be impossible to count the exact number of drops, but the volume of water can be measured at any time. This volume could be any value, eg 2 litres, 2.2 litres or 5.755 litres.

Question

Look at the following statements and decide if the data is discrete or continuous.

• the weight of pupils in class 5b
• the number of chocolates in various 500 g boxes
• the time taken to run 100 metres

Reveal answer

• The weight of pupils in class 5b – continuous. Weight is measurable data and pupils’ weights can take any value.
• The number of chocolates in various 500 g boxes – discrete. This will involve counting the number of chocolates in each 500 g box.
• The time taken to run 100 metres - continuous. Time is measurable data and the time taken to run 100 metres can take any value.

Displaying data

Once data has been collected it is useful to put it in a chart, graph or diagram.

Choosing the right chart to display numerical information is very important. This is because your chart will need to be easily understood by the reader. If you choose an inappropriate chart, your reader may not be able to understand what information is being shown.

Begin by deciding the type of numerical data in order to choose the best type of chart to show the data:

• if your data is made of whole numbers that are counted and not measured, your data is discrete
• if your data is measurable and can take on any value, it is continuous