10-03-2011 11:42 AM
Maybe I'm misunderstanding your question, but GENMOD does not give prediction intervals for individual responses.
There are two confidence intervals that regression routines return. The familiar one is the confidence interval for the mean predicted value. (Most/All SAS regression procedures return this.) The other is prediction limits for an individual response. REG and GLM return this, but GENMOD does not.
For details, see the formulas for LowerM versus LowerI in the regression chapter of the SAS/STAT doc: http://support.sas.com/documentation/cdl/en/statug/63962/HTML/default/viewer.htm#statug_introreg_sec...