Judge a Book by its Cover

Come on designers, you know you judge a book by its cover.  But just how accurate are you?  Test your skills on Judgeby.com, a website that allows you to guess a book's Amazon rating just by looking at its cover.

I was pretty actuate at this.  Which makes me think one of two things: A well designed cover reflects well on a book OR people who write good books are smart enough to appreciate a well designed cover.  More thoughts? (Found through A Collective Knot).