# Grouping continuous data

**Grouping data**

A list of results is called a **data set**. If there are large amounts of data in a data set, then they are segregated into groups. The width of these groups are called **class intervals**.

Using the class intervals, a **frequency diagram** or **histogram** can be drawn.

**Notation for class intervals**

Class internals are written in the following form:

When measuring time in seconds for a given class of frequency, in a table the following is written, for example:

If time is seconds is between 85 – 90 seconds – this is written as 85 ≤ *t* < 90 (this is represented as “time being larger or equal to 85 and less than 90 seconds).

*t *– represents time