Uma, Please help to understand the difference in Clinical line vs SAS Advance Line, What is good to go as carrier ...? ... View more

I suggest you start a new thread with a title something like "No standard error for intercept in NLMIXED" in the Statistics group instead of health care as it may get more attention there. And with the error resolved for this one mark it answered, even if you found the resolution on your own. ... View more

Here is a description of how to get a correlation matrix when your estimate is not positive definite: Computing the nearest correlation matrix - The DO Loop ... View more