Data Intelligence, Business Analytics
Anova makes the assumption that each level of a categorical variable has a normal distribution for the response variable with equal variances. Why notoriously robust, I would look at the data on a trellis-style graph before doing an ANOVA. The y-axis for each subplot will the response variable. Since it is a trellis the scale will be the same for each nominal variable. The x-axis for each subplot will be each level of the nominal variable. Nearly all popular statistics and business intelligence software provide for these graphs now.
This graph will have several uses. 1) You will see which levels of the categories are used. 2) You will see the distribution within each nominal variable. 3) You can look across the nominal variables. Then you can think about what type of modeling approaches to use.
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