Great example of selection / survivorship bias ...
With a touch of history thrown in for good measure.
Selection bias and bombers — The Endeavour
"During WWII, statistician Abraham Wald was asked to help the British decide where to add armor to their bombers. After analyzing the records, he recommended adding more armor to the places where there was no damage! This seems backward at first," http://www.johndcook.com/blog/2008/0...s-and-bombers/