[R] model simplification using Crawley as a guide

2008-06-10 Thread ChCh
Hello, I have consciously avoided using step() for model simplification in favour of manually updating the model by removing non-significant terms one at a time. I'm using The R Book by M.J. Crawley as a guide. It comes as no surprise that my analysis does proceed as smoothly as does Crawley's a

[R] Model simplification using anova()

2008-06-03 Thread ChCh
Hello all, I've become confused by the output produced by a call to anova(model1,model2). First a brief background. My model used to predict final tree height is summarised here: Df Sum Sq Mean Sq F valuePr(>F) Treatment 2 748.35 374.17 21.30