I am doing a GLMM analysis using R, where I have 2 predictor variables (fixed effects) which do not interact, each one has few levels. My factors are “Habitat” and “Year”.
I am interested in doing a post-hoc multiple pairwise comparison between the 4 levels of “Habitat”, to see which ones are significantly different, within every year.
When I use contrast(habitat.dif, alpha=0.05, method="pairwise", adjust="Tukey"), I get a comparison between the averages of the groups across all years and not within every year.
My model is:
abundance.model1
If you just want to know what is happening in habitats 'within every year' without wanting to know if seasons affect each other, you can run the GLM on each year separately :)
I believe your "Year" variable must be a factor. Try to run your regression model with (Abundance ~ factor (Habitat) + factor (Year) +...)
Thank you, Andrew Paul McKenzie Pegman I can do as you suggested.
D. Eastern Kang Sim, Thanks for your reply, but both of my variables are allready factors.
- Badges
- Science method
- Similar topics
- Mathematics
- Statistics
- Statistical Modeling
- Analyses of Variance
- ANOVA