Here's a graph that I put together by plotting some data from the College Board's Annual report on SAT scores from 2009.  SAT scores are plotted on the y-axis, maximum family income on the x-axis.  A pretty strong correlation, no?

In its press release attached to this report, the College Board states that those students who "had familiarized themselves with the test" scored better than those who had not.  While the College Board goes on to say that "one way to practice is to take the PSAT," it's clear that test preparation continues to help those students who can afford to pay for it.  

Isn't it time for test prep to be available to everyone?