Fundamental Concepts on Classification and Statistical Implicative Analysis for Modal Variables

The present work offers some fundamental concepts of the Statistical Implicative Analysis for modal variables and proposes an index to establish the similarity between two modal variables. Expressions to calculate typicality and contribution of the individuals to the classes that are formed in the classification are also presented. This technique is illustrated by two examples, one with binary data, which allows  the coincidence between the formulas presented and the existent for the binary case to be shown, and the other for modal data with more than two modalities.