Someone at the Washington Post is a bit confused about averages.
Basically, Barack and Michelle Obama (you've heard of them, right?) got a mortgage at a rate of 5.625% at a time when the average rate was 5.93% -- and so the Obama campaign finds itself playing defense. But as Nate Silver pointed out, this is evidence that the Obamas have good credit, and as various people commenting there pointed out, it's an average.
Some people get better than average rates. That's true by definition. (Although I suspect that more than half of people get a rate below the mean, because the right tail is probably longer than the left tail.
Personally, I want my presidential candidates to be getting a good interest rate -- because it's evidence that they have good credit, which in turn is evidence for some sort of financial prudence. (Yes, I know, some people with bad credit got there because they got dealt a bad hand. It's evidence, not a proof.) And if someone is good at managing their own money, they might be good at managing the country's money.
And do we really want our president to be average?