Introduction to Data

Types of Variables

Levels of Measurement

This topic looks at classifying variables. I start by defining variables. I then discuss the difference between categorical (qualitative) and numerical (quantitative) variables. I further classify numerical variables as either discrete (countable) or continuous (uncountable). Examples are given of each of these classifications. I then look at classifying variables by their level of measurement. I discuss the difference between the nominal, ordinal, interval, and ratio levels of measurement. Examples are given of variables at each of these levels of measurement.

The following resources can be used to further understand this topic: