Before getting too deeply into those data, try this:Linda S. Gottredson - The General Intelligence Factor
(found on the Amerika links page
General intelligence, plus discipline and a sense of awareness to the world around you and your own motivations, are even more important than inherent musical ability -- you can develop musical ability with some work (even the tone deaf like Robert Fripp have become genius musicians) provided that you have raw ability.
While I am a strict biological determinist, I think that even a hardline view of that position includes the ability of smart people to use self-discipline to become more than they are. There are two fallacies in paying attention to your intelligence without that caveat: (a) you will conclude you are smart, and then stop trying, and justify yourself by claiming that society/God/African-Americans/Caucasians/Satan wronged you, and (b) you will conclude you are unable because you do not have the AVIH++ gene, and therefore do nothing.