Qualitative variation

Qualitative variation (QV) allows us to assess the degree of statistical dispersion in nominal distributions.

Variance is minimized if all cases belong to a single category and is maximized when all cases are qually distributed across all categories. The lower bound of qualitative variation is 0 - when all cases belong to a single category.

The larger the number of categories and the laeger the differences in frequencies across categories, the larger the variance.

Index of qualitative variation (IQV) is defined as a ratio of observed differences to maximum differences.