Regression analysis
Categorical random variables are normally described statistically by a categorical distribution, which allows an arbitrary "K"-way categorical variable to be expressed with separate probabilities specified for each of the "K" possible outcomes. Such multiple-category categorical variables are often analyzed using a multinomial distribution, which counts the frequency of each possible combination of numbers of occurrences of the various categories. Regression analysis on categorical outcomes is accomplished through multinomial logistic regression, multinomial probit or a related type of discrete choice model.