Frequency Distribution of Grouped Data

A grouped frequency distribution is obtained by constructing classes (or intervals) for the data, and then listing the corresponding number of values (frequency count) in each interval. Typically when the difference between the highest number and the lowest number is greater than 15, you might prefer to use a grouped frequency distribution.

The numbers are grouped into intervals, and the frequency of scores in each interval is listed in a separate column.

The intervals can be of any size, but, for ease of construction, a grouped frequency distribution should end up with no more than about 10 groups.

A grouped frequency distribution provides less precise information than does an ungrouped one, because the individual performances are lost. However, the benefit of a grouped frequency distribution is that one can understand any trends in the data at a quick glance

Practice: Answer the following exercises about frequency distribution of grouped data.