⊿ Point. {R} Glossary. ◢ Keyword: N. ◥ University. {q} PhD. {tr} Training. ⚫ UK. ↂ EndNote. ☝️ Weerakkody. Nominal category. Concept in statistics Introduction to nominal data[edit] A variable used to associate each data point in a set of observations, or in a particular instance, to a certain qualitative category is a categorical variable. Categorical variables have two types of scales, ordinal and nominal.[1] The first type of categorical scale is dependent on natural ordering, levels that are defined by a sense of quality. Variables with this ordering convention are known as ordinal variables.
In comparison, variables with unordered scales are nominal variables.[1] A nominal variable, or nominal group, is a group of objects or ideas collectively grouped by a particular qualitative characteristic.[3] Nominal variables do not have a natural order, which means that statistical analyses of these variables will always produce the same results, regardless of the order in which the data is presented.[1][3] Valid performable operations on nominal data[edit] Examples and logical analysis of nominal data[edit]