Ph Do What!?

There is a pseudo-mythic story about Abraham Wald , a Hungarian mathematician, and the US Air Force (USAF) that I'd like to relate to you.  There's some question as to how much of this story is fact, and how much is embellishment, but it's close enough to true to be useful for my purposes.   By the time the US got involved in WWII, the Germans were pretty well entrenched in the lands they occupied.  Part of this entrenchment involved land based anti-aircraft batteries.  These anti-air defenses wreaked all merry havoc on US bombers.  In attempt to address this, the USAF turned to the Statistical Research Group at Columbia University, where Wald was a member.  They wanted an analysis of where their planes were being hit, based on where the holes were in the planes they got back.  The statisticians went to work, and found a locations that had statistically many more holes than other locations.  (I would be remiss if I didn't tell you at ...