[R] AIC, glm, lognormal distribution
Benjamin M. Osborne
Benjamin.Osborne at uvm.edu
Mon Dec 13 03:39:48 CET 2004
I'm attempting to do model selection with AIC, using a glm and a lognormal
distribution, but:
fit1<-glm(BA~Year,data=pdat.sp1.65.04, family=gaussian(link="log"))
## gives the same result as either of the following:
fit1<-glm(BA~Year,data=pdat.sp1.65.04, family=gaussian)
fit1<-lm(BA~Year,data=pdat.sp1.65.04)
fit1
#Coefficients:
#(Intercept) Year2004
# -1.6341 -0.2741
#Degrees of Freedom: 84 Total (i.e. Null); 83 Residual
#Null Deviance: 1.521
#Residual Deviance: 1.476 AIC: -97.31
fit1<-glm(BA~Year,data=pdat.sp1.65.04, family=quasi(link="log"))
# also gives the same result but returns AIC: NA
## Is it possible to model a lognormal distribution without having to transform
## the data themselves? (i.e.:
fit1<-lm(log(BA)~Year,data=pdat.sp1.65.04)
Thanks in advance,
Ben Osborne
--
Botany Department
University of Vermont
109 Carrigan Drive
Burlington, VT 05405
benjamin.osborne at uvm.edu
phone: 802-656-0297
fax: 802-656-0440
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