Re: [Phys-l] probability problem

[Stefan Jeglinski <jeglin@4pi.com>]

Correct me if I'm wrong but I want to understand your point:

> The standard analysis of the Monty Hall problem makes clear that you 
> are twice as likely to win the car if you DO switch, but that 
> analysis ignores the significant possibility that Monty might only 
> show you the goat and allow you the opportunity to switch if you have 
> already chosen the curtain with the car behind it.

You're saying that in "real life" Monty might have unstated motivations, no?


> In this case, it seems to me that the probability of having two aces 
> in case 3 is likely to be significantly lower than the standard 
> analysis would suggest simply because it would seem odd for the 
> observer to be more surprised by the appearance of the ace of spades 
> than by the appearance of two aces--i.e., the simple fact that the 
> observer said "Wow" would lead me to believe that it is *very* 
> unlikely that I have two aces.

Likewise the dealer in saying "wow"?

I take it your point is that neither issue changes the problems, as 
stated, but that in "real life" there may be other considerations to 
think about?

It is mildly interesting to me, but I have not thought it through, 
that if the dealer says "wow you have the ace of spades" and I ask 
"do I also have at least 1 spade?" and he says "yes" then I have not 
really changed any odds - or have I? In the originally stated 
problem, these 2 scenarios exhibited different entropies, I tried to 
claim. And yet having the answers to both now, in this particular 
order, seems to do me no good.

I hate probability problems.


Stefan Jeglinski