Dear R users,
Recent changes to the MuMIn package now means that the model averaging command
(model.avg) no longer returns confidence intervals, but instead returns zvalues
and corresponding pvalues for fixed effects included in models.
Previously I have used this package for model selection/averaging following
Greuber et al (2011) where it suggests that one should use confidence intervals
from model averaging to assess whether your fixed effects have an affect or not
(If confidence intervals do not span zero then variable has an affect).
Can anyone tell me why MuMIn now gives z-stats and p-values and whether these
should be used to assess the 'significance'/importance of variables when model
averaging?
Heres the example code of what I'm doing....
#-------------------------------------------------------------------------------------#
ps<-lmer(tranPS~(
Sex+
Age.Cat2+
TOTAL+
Propfarm+
Maize+
TOTAL:Propfarm+
Maize:TOTAL+
Maize:Propfarm+
(1|Socialgroup)+(1|Year)+(1|Tattoo)),REML=FALSE, data=propspec)
pss<-standardize(ps,standardize.y = FALSE)
psdrg<-dredge(pss)
summary(model.avg(get.models(psdrg,subset=delta<2)))
#-------------------------------------------------------------------------------------#
REf -Grueber, C.E., Nakagawa, S., Laws, R.J. & Jamieson, I.G. (2011) Multimodel
inference in ecology and evolution: challenges and solutions. Journal of
evolutionary biology, 24, 699-711.
Any help would be much appreciated
Regards
Andrew Robertson
PhD student
Centre for Ecology and Conservation
University of Exeter, Cornwall Campus
Tremough, Cornwall. TR10 9EZ
UK
Tel: 01326 371852
Email: ar...@exeter.ac.uk
Web page:
http://biosciences.exeter.ac.uk/staff/postgradresearch/andrewrobertson/
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