The nominal scale consists of a set of categories that provide different names for different categories. The nominal scale does not make any quantitative distinction between categories. Favorite color is an example of a variable measured on the nominal scale. We can name colors, but we cannot make any meaningful quantitative (numerical) distinction between the categories. Does blue and any greater or lesser value than red as a favorite color? No. For this reason, favorite color is a nominal variable.
It can be confusing when numbers represent nominal level variables. Sometimes, numbers make convenient names. Think of the numbers on athletic jerseys. So long as these numbers serve only to name a particular player and do not provide any quantitative information (such as better players getting higher numbers), then the scale is still nominal. Do not let the presence of numbers confuse you.
The Nominal Scale provides only a name, and the data are neither ordered nor measured.
Last Modified: 06/29/2018