From the linked study:
Quote
The study's most disturbing finding, the authors say, is that neither boys nor girls get many tough math questions on state tests now required to measure a school district's progress under the 2002 federal No Child Left Behind law. Using a four-level rating scale, with level one being easiest, the authors said that they found no challenging level-three or -four questions on most state tests.

I think that pretty much invalidates this data for judging anything about the right tail.