I'm significantly above average, and I've got the test scores on aptitude tests to prove it.
Now, that doesn't always help matters. Applying yourself, repeatedly, to things that are elementary for you is difficult, and if you can't do THAT people don't let you do anything more interesting.
For what it's worth, though, I have far fewer excuses to do poorly than your average bear, and I can prove it. Much to my charign.