Hi Bruce,

I was waiting to see your 'answer' to this...

I was feeling that both answers were 'right' too, from the simple perspective that each took the problem from a different point in 'time'. One from the start (3 doors to consider) and the other from after the first door was opened. My view was also to start with most 'facts' as possible in hand (ie only two doors left).

Cheers,

Jim N

>>Hi Al,
>>
>>>1. There are exactly 2 doors remaining.
>>
>>That's the point. 2 doors are remaining which means, there are more doors involved. They point is, you can't simply remove one door from this 3-door game, because statitistically, you don't know which one. If you remove one there's 1/3 probability, that you remove the door with the boat. This 1/3 is exactly, what must be added to the 50% probability of your 2-door game, ie. 0.5*1.33 = 0.66, the probability that changing gives you the right door.
>
>Hi Christof - I see I missed all the action over the weekend :) This is an old statistical problem, and invariably there is confusion and disagreement on the solution, even when the problem is stated clearly (in which case the 2/3 solution is the right answer for the usually given 3-door problem).
>
>In this case, from what I've read, both sides are right for the way in which they stated their solution - it's a matter of interpretation, unless the problem is stated more clearly - in this case, it appears the problem was not stated too clearly, so either answer is correct if based on the stated premises...