For a nominal explanatory variable, tables typically present the difference between k-1 categories and a reference category, and significance tests for that. The -contrast- command makes it easy to instead get the contrast between each of the categories and the grand mean (unbalanced/asobserved), and the significance test associated with that. In many contexts, though, I think the contrast that folks would find most informative would actually be the contrast between a category and the mean of the other categories (again, unbalanced/asobserved).
As far as I can figure out, -contrast- allows you to compute this for either the first or last category for an ordinal variable, but is there a way to get this for all categories?
As far as I can figure out, -contrast- allows you to compute this for either the first or last category for an ordinal variable, but is there a way to get this for all categories?
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