I am trying to compare males and females using ANCOVA while also correcting for phylogenetic relatedness. Mass is the covariate and I want to know if males and females have different scaling slopes and intercepts. I have calculated phylogenetically-corrected slopes for males and females that can be overlaid onto the original data space, but cannot figure out how to manually fit them in order to run the ANCOVA model. If I perform an ANCOVA as is, the slopes are based on the raw (phylogenetically-uncorrected) data.
I would prefer an interactive explanation if possible, but any help will be greatly appreciated!