Its really just as simple as seeing the glass as half full or half empty.  I'm surprised they guy made any money on a book like that.  He was not even a statistician so he wasn't even an expert in the field. Not that you'd have to be one  to write a book like that.  Reminds me of all the dire statistics  concerning bad habits, like smoking.  1 in 4 will get lung cancer. Yes, but 3 in 4 will not.