Flipping for answers

A statistics major was completely hung over the day of his final exam. It was a true/false test, so he decided to flip a coin for the answers. The statistics professor watched the student the entire two hours as he was flipping the coin ... writing the answer ... flipping the coin ... writing the answer. At the end of the two hours, everyone else had finished the exam and left the room except for that lone student. The professor walked over and said, "Listen, I see that you did not study for this statistics test, you didn't even look at the exam questions. If you are just flipping a coin for your answers, what in the world is taking you so long?"
Still flipping the coin, the student replied "Shhh! I am checking my answers!"