And that's not even the worst of statistical illusions. After reading about, for example, Simpson's paradox http://en.wikipedia.org/wiki/Simpsons_paradox http:

And that's not even the worst of statistical illusions. After reading about, for example, Simpson's paradox http://en.wikipedia.org/wiki/Simpsons_paradox http://en.wikipedia.org/wiki/Simpsons_paradox I concluded I'll always be very wary of using statistics for anything. It's a powerful tool, but also very easy to shoot yourself in the foot with. (Or to get deceived by. And they don't even need to know statistics better than you in order to fool you with some reasonable-looking analysis!)