The Types of Data

Data Types, in statistics, allow us to organize and select appropriate processing procedures and descriptors.

There are two major data types: Categorical (aka Qualitative) and Quantitative (aka Numeric) . It is convenient to represent data (data collections or set) by variables. Thus a variable can also have its type (categorical or quantitative). Categorical variables (data) may be of Nominal or Ordinal type. Furthermore, quantitative variables may take on either discrete values (be subsets of integers, ) or continuous values (be subsets of real numbers, ). A continuous variable may be of Ordinal, Interval or Ratio type whereas a discrete variable may be of Ordinal, Interval type.

A few examples of variable (data) types with respect to their mesurement levels (scale) are shown in Figure 1.

Figure 1. Examples of Data Types