Grouping data

When there is a large number of possible outcomes, you will usually need to group the data. To do this, first decide on your class intervals based on the range of likely possible answers.

Investigation example

You are carrying out a survey to determine the number of magazines bought by your classmates in the past year. The possible answers are likely to range from {0} to {100}, so you may draw a tally chart with groupings similar to this one:

Tally chart showing grouped data

The completed frequency table is known as a grouped frequency table.