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contrasts for generalized linear model
2 messages · Wade Wall, espesser
Dear Wade, If I understand well your data, year (in fact, TSB) is the (main ?) fixed effect, and is not a random term. I suppose there are levels enough for pop. I think your model would be something like : lmer(flowering ~ TSB +(1|pop) ,family=binomial, data=....) I would use successive difference contrast for the 3 levels factor TSB. see contr.sdif() in library(MASS). Regards Robert Le 25/05/2011 17:15, Wade Wall a ?crit :
Hi all, This question has perhaps been answered before, but I can't find a reference to it. I have a data set that consists of binomial data (plant flowering) and time since the plant was last burned (1, 2, or 3 years ago). There appears to be a main effect ( flowering is reduced in year 1), but I want to compare years 2 and 3 to see if flowering is decreasing by year three. The model that I included random effects of Year (year data collected) and population (multiple pops). The data set basically looks like this: Pop Year TSB Flowering 1 2008 1 1 1 2008 1 0 . . . . . 24 2010 3 0 24 2010 3 1 What is the best way to set up contrasts for binomial data in R? Is it basically the same as with an ANOVA? Thanks for any information. Wade [[alternative HTML version deleted]]
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