Anecdotal.
I've made more than enough mistakes in judging individuals. Doing it based on the colour of their skin is just the most egregious.
I've met white slackers, I've met chinese pot heads and I've worked with black men who humble me with the grasp of subjects I'm considered an expert in.
It's just a stupid (and I don't use that word lightly) way to judge someone.
Good luck.