What is the primary characteristic of nominal data?

Nominal data is primarily characterized by its representation of categories without any numerical value. This means that it classifies observations into distinct categories based on qualitative attributes or characteristics, without implying any order or ranking among those categories. For example, nominal data could include types of fruits (e.g., apples, oranges, bananas) or colors (e.g., red, blue, green). Each category is unique and simply labels a certain group without any inherent value or order, which is essential to understanding nominal data's nature and utility in analyses.

In contrast, the other options relate to types of data that imply some level of measurement or ranking, which does not pertain to nominal data.