Alan B. Pearce wrote:
>>> Is that really correct? Surely the host always picks a known non-prize
>>> door,
>>> and gives the contestant a second choice, whether or not they picked
>>> the correct one?
>>>       
>> That's my understanding as well, the hosts behaviour is always the same.
>> After the contestant selects a door, the host will always open one of
>> the other doors with a goat behind it.  The behaviour is the same
>> whether or not the contestant picked the car on his first choice.
>>     
>
> So then the first choice is irrelevant, and it comes down to 50:50 chance 
> that you pick the right one. 
>
>   

Seems like a type of a frame-of-reference question to me, thus both 
answers (1:1, 2:3) are correct.

 From the perspective of the original three closed doors: 2:3
 From the perspective of the remaining two closed doors: 1:1

But I'm probably wrong.
Daniel

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