Joined: Jan. 2007
I made thew following reply 2 times in this thread (http://www.uncommondescent.com/archives/2065), and made one inquiry as to why it is not appearing; but I have yet to see it.
According to this article (http://query.nytimes.com/gst/fullpage.html?sec=health&res=940DE7D6163AF930A35752C0A96E948260), there are about 3 mass murders in the US per month. So the odds of any 2 happening on a specified day are:
(3,2) 1/30*1/30*29/30 or about 0.32 %
The odds of any two happening on any day are:
(2,1) 1/30*29/30, or about 6%.
That's assuming my rusty combinatorics are still correct...