Re: [R] constraining correlations

2007-10-12 Thread Matthew Keller
Hi all, I want to constrain observed correlations to be equal. E.g., I want to find the ML cor(x,y) and cor (w,z) given that cor(x,y) must be equal to cor(w,z). I've received some suggestions that were sent directly to me, but based on these responses, I'm afraid I wasn't clear enough in my orig

[R] constraining correlations

2007-10-11 Thread Matthew Keller
Hello, I've searched for an answer to no avail. I am wondering if anyone knows how to constrain certain correlations to be equal. I have family data with 2 twins per family plus up to 2 siblings. I would like to somehow constrain all the sibling correlations (twin-sib and sib-sib) to be the same w