Data Types
Data Types
We often begin exploratory data analysis by examining the types of data that occur in a table. Although there are multiple ways of categorizing data types, in this book we discuss three broad types of data:
- Nominal data, which represents categories that do not have a natural ordering. For example: political party affiliation (Democrat, Republican, Other), sex (male, female, other), and computer operating system (Windows, MacOS, Linux).
- Ordinal data, which represents ordered categories. For example: T-shirt sizes (small, medium, large), Likert-scale responses (disagree, neutral, agree), and level of education (high school, college, graduate school). Ordinal and nominal data are considered subtypes of categorical data.
- Numerical data, which represents amounts or quantities. For example: heights, prices, and distances.
We refer to these types as statistical data types, or simply data types.