.com/resources/papers/proceedings12/335-2012.pdf" class="external-link">Yang <em>et al</em> 2012</a>. This multinomial extesion treats a single multinomial variable as multiple non-redundant dichotomous variables and use the Mahalanobis distance. The off diagonal elements of the covariance matrix on page 3 have an error, and need negation. In weighted data, the same definitions can be used except that the mean and standard deviation estimates are weighted estimates (<a href="https://pubmed.ncbi.nlm.nih.gov/