The mode

The mode is the number which occurs most often in a set of data. There can be more than one mode.

Have another look at Kieran's results and find the mode:

10  14  10  12  10  11  12  10  11  9  12

We need to identify the number that appears in this set of numbers the most. Sometimes it helps to list the numbers in numerical order:

9  10  10  10  10  11  11  12  12  12  14

Here we can see that the number 10 occurs most often, so 10 is the mode.

From a frequency table, it is even easier to spot the mode.

There are four CDs with 10 tracks. The other numbers of tracks do not occur four times or more, so 10 is the mode.

Group data and modal classes

When we have a lot of categories, we sometimes need to group the data.

This table shows the shoe sizes of 100 people in a shop:

The groups 10-19, 20-29, 30-39 and 40-49 are called classes.

The class with the most people is 40-49. We therefore call this the modal class.