Earlier quoted context omitted.
Could this be explained in part by people who are good at math tending to make more money than people who are bad at math? http://media.collegeboard.com/digitalServices/pdf/research/2...
It has nothing to do with that. Wealth in this country is in no way correlated to math ability.
I ask because it is well known that math ability is correlated with educational achievement, and level of education is known to be correlated with income. Putting these two together, I would suppose that math ability is correlated with income.