search for: monozygotic

..."outer" to the clustering variable---zygosity. Dependent variables are all parental (mom, dad separately of course) psychiatric diagnoses. In my data, twin pair ID is the clustering variable; correlations are expected to be exchangeable but substantially different between members of monozygotic twin pairs and members of dizygotic twin pairs. Hence, in my analyses, the variable that's "outer" to twin pair is monozygotic vs. dizygotic which of course applies to the whole pair. nlme() does all that but requires quasi-continuous responses, according to the preface/intro of...