I have to calculate a sample size for a logistic regression polytomic multifactorial.
The ordinal response has 3 modalities (mild, moderate, severe)
There are 9 binary (yes/no) variables to include in the model and 1 variable with 3 modalities.
Thanks by advance.
I think that the PROC SAS to do that does not exist yet but i found an article (http://www.childrens-mercy.org/stats/weblog2004/OrdinalLogistic.asp) where there is the formula to calculate the sample size.