Not wanting to add fuel to the fire here, but I do remember reading something on the net in regards to reading comprehension and African Americans. I googled it, and came up with this:
http://www.findarticles.com/p/articles/mi_...301/ai_n9215415
It's quite in-depth, so I only read the first page, but I think it more or less explains the point Evman is making. It's a little old as well (I believe the date is 2001) and not being a statistician I couldn't tell you if it would affect the results or not.