I use Australian twin sample biometric data to test my scripts, but there is something unclear with zygosity variable: it has 10 levels instead of 5 (as declared on help page). How should I actually interpret these levels?
I think 1:5 is young, and 6-10 is an older group. (correct me, IBG workshop experts, if I am wrong).
So, you're right. historical note: I did the twinData.Rd file back in 2010 and didn't realise the data re-used zyg to encode young and old sample blocks.
I've updated the rd to reflect this in the trunk...
But, saying zyg == 1 will get you a cohort of MZFFs, so there's nothing wrong in what you are doing. It's just around half the sample.
Also added refs to the Rd (Martin and Jardine, 1986).
Also, have a look at Neale and Maes Methodology book to learn a little bit more.
Thank you a lot! I guessed something like this.