[R-sig-ME] MCMCglmm Heterogenous Residual Variance in a Categorial Model

[FERNANDEZ Ana maria]

Dear List,

I was wondering what the recommendation is for structuring residual variances in the context of a categorial model when you have a sex interaction in the random term of the model (where animal is the pedigree structure).

MCMCglmm course notes have a brief recommendation about sex interaction and allowing the sexes to have different residual variances: "3.4 Heterogenous Residual Variance To be started... In short - if you’ve fitted a sex by dam interaction I would always allow the sexes to have different residual variances. Use rcov=∼idh(sex):units.”

But the conflict that I am coming across is another recommendation about how the residual term should be- or needs to be- fixed in a categorical model.

I have a case-control binary response variable and I want to look at the sex effect interaction.

Let me know if you need more detail.

Thanks!
Maria



Ana Maria Fernández Pujals
A.Fernandez-2 at sms.ed.ac.uk<mailto:A.Fernandez-2 at sms.ed.ac.uk>




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