Qualitative and quantitative data

In a nutshell

Data comes in three forms: continuous, discrete and categoric. Each type of data has different characteristics. The type of data helps to determine how the data should be presented, whether it be a table, graph or chart.

Qualitative data

Qualitative data is data that is only available as words, and so is also described as categoric data. Because of this, there is no way to make inferences about data that has not been recorded, so line graphs and scatter graphs cannot be used for this type of data.

Example 1

Vehicle type, colour and taste are all types of categoric data.

Quantitative data

Quantitative data is data that is numeric, and comes in two forms. It is either discrete or continuous.

Discrete data

This is numeric data that can only take specified values. This means that there are certain numbers that it is impossible for the data to be, within any range.

Example 2

Shoe size, number of people in a school and number of sweets in a packet are all types of discrete data.

Continuous data

This is numeric data that can take any value within a range. Unlike discrete data, this means that for any number within a specified range, there can exist data with this value. Line graphs can be used for this type of data, which allows us make inferences about data that might not be available.

Example 3

Height, weight and time are all types of continuous data.

Data representation

Data graphic	Variable type	Example
Scatter graph	Discrete or continuous
Line graph	Discrete or continuous
Bar chart	Categoric or discrete
Pie chart	Categoric or discrete