The second form is applicable only to summarized binomial response data. The variable events or trials may take noninteger values. The response variable can be numeric or character. The ordering of response levels is critical in these models. Responses for the Poisson distribution must be positive, but they can be noninteger values.
Explanatory variables can be continuous or classification variables.
Classification variables can be character or numeric. Interactions between variables can also be included as effects. Columns of the design matrix are automatically generated for classification variables and interactions. The syntax for specification of effects is the same as for the GLM procedure. It is ignored if specified for other cases.