I can't believe I forgot to include this one in the statistics comic master post considering I've used it on an exam before.
Hell, my eighth grade science class managed to conclusively reject it just based on a classroom experiment. It's pretty sad to hear about million-dollar research teams who can't even manage that.
"Null Hypothesis" - Copyright CC BY-NC 2.5 by Randall Munroe, xkcd.com
keywords: hypothesis testing; null hypothesis; study; reject;