Bullet Hole Statistics

I have been studying for my statistics exam today and I remembered my professor telling us this story on the first or second day of class to try to motivate more students to switch their major to statistics. She told us how statistics can be used in many different fields and has even been used as a military advantage during war time.

During World War II, a statistician (whose name I forgot) was hired by the military to determine where more armor should be put on the plane. The statistician checked out the planes that returned from combat and saw where the most bullet holes were. Then, after mapping that out, he decided to put more armor where there WERE NOT any bullet holes.  Can you guess why?

Because this is where the planes where shot that didn't return home.

Very clever, no?