What type of variable is a nominal variable?

A nominal variable is one that consists of categories which do not have a natural order or ranking. This type of variable is used to label variables without any quantitative value. For example, categories such as gender, race, or blood type are nominal variables because they classify individuals into distinct groups without implying that one group is better or higher than another.

In contrast, a variable with a defined rank order refers to ordinal variables, which involve a sequence or scale where the order matters. A variable representing measurements or quantities pertains to continuous or discrete variables, where numeric values are assigned that can be measured. Lastly, the idea of a variable limited to one category does not capture the broader concept of nominal variables, which can include multiple categories but remain unordered. Thus, the defining characteristic of nominal variables is indeed their lack of any intrinsic order among the various categories.