NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: The Darn Old Cocked Hat - the sequel 1
From: Geoffrey Kolbe
Date: 2013 Mar 17, 16:03 +0000
But surely Don, once Monty has revealed that one of the doors does not hide the prize, there are only two doors left and we don't know behind which door the prize sits. So, regardless of which door was chosen first, the probability that the prize is behind each of the remaining two doors is then just 1/2, isn't it?
If this is not the case, why not?
Geoffrey
From: Geoffrey Kolbe
Date: 2013 Mar 17, 16:03 +0000
I would absolutely change my choice.
My first pick has a 1/3 chance of being correct. There is a 2/3 chance that the big prize is actually behind one of the other curtains. Because Monty always reveals an empty curtain, the remaining curtain's odds now become 2/3. The odds for my initial choice are unchanged; they are still only 1/3.
Don Seltzer
But surely Don, once Monty has revealed that one of the doors does not hide the prize, there are only two doors left and we don't know behind which door the prize sits. So, regardless of which door was chosen first, the probability that the prize is behind each of the remaining two doors is then just 1/2, isn't it?
If this is not the case, why not?
Geoffrey