The nominal level

The first level of data, the nominal level, has the weakest structure. It consists of data that are purely described by name. Basic examples include blood type (A, O, AB), species of animal, or names of people. These types of data are all qualitative.

Some other examples include:

• In the SF Job Salary dataset, the Grade column would be nominal
• Given visitor logs of a company, the first and last names of the visitors would be nominal
• Species of animals in a lab experiment would be nominal