On Mon, 2006-04-17 at 10:17 -0400, Gong, Yanyan wrote: > Hi, I am trying to runn a age-period-cohort model, but here is what I am > having problem with, hope you can help me! > > This is what I am trying to do: > sumzero_a<-((A-min(A))/5+1) - mean((A-min(A))/5+1) where A is my age > variable (numeric, the mid-point of a five-year age group), but I got the > following error: > > Error in min(..., na.rm = na.rm) : invalid 'mode' of argument > > I am pretty sure I have the variable "A" in my data, can you see why this > happens? > > Thanks. > > Yanyan
'A' does exist or you should get something like the following: > min(A) Error in min(A) : object "A" not found More than likely, 'A' is not a numeric vector. It could be a character vector, a list or some other non-atomic data type. It is not a factor, lest you get something like the following: Error in Summary.factor(..., na.rm = na.rm) : min not meaningful for factors See ?is.atomic for some additional information. Without your code, it would be difficult to ascertain how 'A' is created. However, consider the following example: > L <- LETTERS > L [1] "A" "B" "C" "D" "E" "F" "G" "H" "I" "J" "K" "L" "M" "N" "O" "P" "Q" [18] "R" "S" "T" "U" "V" "W" "X" "Y" "Z" > min(L) Error in min(..., na.rm = na.rm) : invalid 'mode' of argument > mode(L) [1] "character" I would use: str(A) or mode(A) to see what 'A' is. That should give you a hint. HTH, Marc Schwartz ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html