Direzioni di massima risolvenza dell’indice di Mortara: confronto con i più consueti indici di connessione normalizzati

The concept of resolution has been recently introduced (see Zanella (1988)) as a possible criterion for comparing the most usual descriptive normalized measures of association like those of Goodman-Kruskal, Cramèr, Mortara and of the entropic type. For a given contingency table, the paper refers to the problem of the existence of directions along which Mortara's measure of association is more (not less) resolving than any of the others above mentioned (admissibility). In the first part of the paper stationary directions, for which the resolution function of Mortara's measure of association takes its maximum value, are found. The second part of the study deals with the comparison of the above mentioned measures of association along the former stationary directions and that is done from a theoretical as well as numerical point of view. The following conclusion has been reached Mortara's measure of association can be considered as being admissible in regard to the others, as far as square contingency tables are concerned.