I want to compare data that proportions among three different groups e.g.:
ID Group Prop.Nitrogen 1 A 0.89 2 A 0.85 3 B 0.92 4 B 0.97
When I look at diagnostic plots for linear models on the transformed and un-transformed data they look very similar with no obvious problems, and there are only small differences in estimated parameters. However, I'd still like to be able to say something about how well the model fits the transformed and untransformed versions of the data - I know I can't compare AIC values directly. Is there a correction and I can make to examine this? Or should I be taking a different approach?