Hi- I'm try to run a GAM with a Gamma distribution, but am getting an error message that there are non positive values allowed for the gamma family. I do not have any negative values for my response or explanatory variables. cod.fall.gam2.kept<-gam(y~s(b,bs="cr",k=4)+s(e,bs="cr",k=4)+f+s(g,bs="cr",k=4),data=cod.fall,family=Gamma) Error in eval(expr, envir, enclos) : non-positive values not allowed for the gamma family Thanks Sally Sally Roman Fisheries Technician University of Massachusetts, SMAST 200 Mill Rd., Fairhaven, MA 02719 sroman at umassd.edu 508-910-6379
GAM with a Gamma error structure
2 messages · Sally Roman, Gavin Simpson
On Sun, 2008-11-16 at 17:58 -0500, Sally Roman wrote:
Hi- I'm try to run a GAM with a Gamma distribution, but am getting an error message that there are non positive values allowed for the gamma family. I do not have any negative values for my response or explanatory variables. cod.fall.gam2.kept<-gam(y~s(b,bs="cr",k=4)+s(e,bs="cr",k=4)+f+s(g,bs="cr",k=4),data=cod.fall,family=Gamma) Error in eval(expr, envir, enclos) : non-positive values not allowed for the gamma family
Non-negative is *not* non-positive. Do you have zero values in the response? This would cause the error you are getting. HTH G
Thanks Sally Sally Roman Fisheries Technician University of Massachusetts, SMAST 200 Mill Rd., Fairhaven, MA 02719 sroman at umassd.edu 508-910-6379
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