Frequency Distributions

Frequency

The frequency of an event is how often it occurs.

Example

Frequency Distribution Table

We can count how many times each score occurs in a list of data and collect them together in a frequency distribution table.

Example

Here is a list of how many times Alice has landed in the wading pool over the past fortnight:

It's easier to work out how many times each number of landings occurs if we put the numbers in order: Then we can count up the number (frequency) of times each number of landings occurs and put the results in a frequency distribution table:

We can use this table to determine all sorts of interesting things about our data. For example,

• The most common number of landings made by Alice was 7
• She achieved most numbers of landings twice.

A frequency distribution table lists all the possible values that occur in a data set and how many times they occur (their frequencies).

Example

Sam's maths teacher gives his class a weekly pre-test to see how well they understand the background material required for the next topic. Here are Sam's marks on the tests for the first 12 weeks of the year:

Sam's marks can be placed in a frequency table as follows

We can also group Sam's marks into different ranges. In the table below, each range is a group of 3 marks. The frequency is the sum of the frequencies for the marks in each range.

You can read more about grouping values in frequency distribution tables in the article on grouped frequency distributions.

Graphing Data

Creating a frequency distribution table is a good first step in displaying your data graphically. Once your data is tabulated, you can choose to display it using a number of different methods including pie charts, bar charts and line graphs. You can read more about these methods in the article on displaying your data.