Windows 10 64-bit, R-Studio, R version 3.4.3
Several questions relating to groupedData: (1) I am trying to create a groupedData object that can be used to run an analysis that I have been able to urn using lmer. When I include the interaction terms in the groupedData opbject I get an error message stating that + is not meaningful for factors. How do I include factors in my model? See code and error below. (2) I have read the help file for groupedData multiple times. I am unable to understand the meaning or, or the use for the inner= and outer= parameters in the call to groupedData. Can someone either explain the meaning of these parameters or refer me to a source that give a clear explanation? > fit0 <- > lmer(THmean~INTRVNTN+factor(TimePtID)+INTRVNTN*factor(TimePtID)+(1|PatientID),data=smalldata) > sdgd <- > groupedData(THmean~INTRVNTN+TimePtID+INTRVNTN*TimePtID|PatientID,data=smalldata) Warning messages: 1: In Ops.factor(INTRVNTN, TimePtID) : �+� not meaningful for factors 2: In Ops.factor(INTRVNTN, TimePtID) : �*� not meaningful for factors Thank you, John John David Sorkin M.D., Ph.D. Professor of Medicine Chief, Biostatistics and Informatics University of Maryland School of Medicine Division of Gerontology and Geriatric Medicine Baltimore VA Medical Center 10 North Greene Street GRECC (BT/18/GR) Baltimore, MD 21201-1524 (Phone) 410-605-7119 (Fax) 410-605-7913 (Please call phone number above prior to faxing) [[alternative HTML version deleted]]
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