1A. Types of Data
Categorical (qualitative)
Labels or qualities with no numerical meaning
- Nominal: unordered and mutually exclusive labels - e.g., eye colour, unit code
- Ordinal: ordered labels - e.g., educational attainment (primary / secondary / tertiary)
Numerical (quantitative)
expressed as quantities
- Discrete: distinct countable values - e.g., number of kangaroos
- Continuous: any value within a range - e.g., weight, temperature
- Interval: values that have a meaningful interval between data points but does not have a meaningful zero - e.g., shoe size
- Ratio: a meaningful interval between data points with a meaningful zero - e.g., length
Scale data
Scale data is used to describe numerical data that has a meaningful scale. Interval and ratio data are often referred to as scale data.
Binary data
Only two outcomes are possible (yes/no, success/fail), also called dichotomous
Bivariate data
each case includes two measurements (used in correlation and regression)
Source
Oxford Brookes University. (2025). Types of data. Retrieved June 7, 2026, from Oxford Brookes University website: https://www.brookes.ac.uk/students/academic-development/maths-and-stats/statistics/types-of-data