Author: Uri Blass
Date: 12:21:00 09/27/02
Go up one level in this thread
On September 27, 2002 at 15:09:58, Rolf Tueschen wrote: >On September 27, 2002 at 14:31:50, Uri Blass wrote: > >>On September 27, 2002 at 14:12:34, Peter Berger wrote: >> >>>On September 27, 2002 at 14:04:01, Uri Blass wrote: >>> >>>>I am sure that I am right. >>>>Marilyn was also right because she answered a different question. >>>> >>>>The probability after knowing that the *not knowing* Monty >>>>took away all the no other no car door is 1/2. >>>> >>>>Suppose I choose place 1 and you choose place 2. >>>>Now the not knowing Monty take away 3-1000000 and we see that there are >>>>no cars in them. >>>> >>>>Do you agree that the probability that I am right is equal >>>>to the probability that you are right? >>>> >>>>The same happens if the story does not include you and if >>>>I know that the host is going always to open doors 3-100000 >>>>because I can imagine a friend that choose door number 2. >>>> >>>>Uri >>> >>>That's not the equivalent setup, Uri. >>> >>>This is more like it: >>> >>>Imagine you stand at door 1, I stand at door 2 and the not-knowing Monty opens >>>doors 2-999999 by a random order. >>> >>>By some incredible luck number 2 is the last one left and still no car showed >>>up. >>> >>>Then he asks you: Mr Blass, do you want to switch or keep with your first >>>choíce. What would you do ;-) ? >>> >>>Peter >> >>I think that the chances are 1/2 >>Suppose that I know that the starategy of the not knowing host >>is always to open doors 2-999999 after I opened door 1. >> >>I can imagine a friend that stand at door 1000000 >>I and my friend have the same chances to be right. >> >>one and only one of us is right and it means that >>the probability for me to be right is exactly 1/2 in case that >>some incredible luck happened. >> >>Uri > >Uri, you are right - if the two of you stand in front of the two doors left, >because the others were taken by the host, then you both have a 50% chance to >get the car. It's strang because Peter although not understanding me but making >public somewhat like prejudices about me for my sinister intentions, Peter >brought up the good example. I don't know why nobody understands it. If you too >made your choice in the case above and the other 99 billion doors were taken by >the host, then you both have 50%. > >Now two adds. > >You said that the host was not-knowing (where the car is, right?). Well, do you >really believe in magic, Uri? You believe that it would be possible - not >knowing where the car is, to prevent that he opens a door with the car??? >Unbelievable. Because it means that he had the chance that one of you had the >car. <g> > >Of course he must know it. > >But then this case. Let's see. You two chose a door, right? And now he knows >where the car is. Now two possibilities. Either he opens all the doors or he >leaves out one door! Now what does it mean???? > >If he opens all the rest one of you has the car. If he does not open a special >car in the end? THEN the car must be there. LOL > >So the game is only a game if it's said before that in the case the two of you >chose a door then the host must leave a third door he doesnt open. Now you must >say in consistence with your general opinion about Monty Hall and me (?) that >the car is exactly behind this third door! > >Of course this is nonsense. Because now all doors have a 1/3 chance to keep the >car. > >If you were allowed to have the first choice which door would you choose, > >-- your first chosen one > >-- the door of the other guy or > >-- the door the host left you? > >Now the third add: > >I have 1 million doors in my Rolf Show. > >I have 1 million guests, ok!! You included, Uri. > >You all choose a door. > >Now I know where the car is. > >What is the probability for each of you??? > >Ok, 1/1 million. > >One of you has chosen the car, right? > >Now I open all the doors of 999998 players andleave 2 doors. YOUR door and one >other guy's door. > >Now forcedly with all the people here you should say, well Rolf, I switch, >because now I know that I have a 999999/1 million chance (it's almost p=1) that >the car is behind that door of the other guy over there. > >Would you really say that? > >Or was the choice of the other guy as good as yours?? > >Well, now I have reveiled the whole myst of the Marilyn fever. Because you >understand now that the two of you at the end both have a 50% chance to win the >car. Either you stick if being asked or you switch. And I as the host did NOT >increase the probability of the door I left closed, the door of your partner. >Get it? Please ask if something is not understood here. I'm not jolking or >making nonsense. > >Uri, if you say yes to my solution in this case here, then you must also say yes >to the other case, the original question. It's always 1/2 in both cases. > >QED > >Rolf Tueschen The difference is that in the original question I know that the host is not going to open my door when in this case I could not know it in the beginning of the game. 999998 people in your story had the bad luck that the host opened their door and told them that they lost and the I could not know in the beginning of the game that I am not going to be one of them. Uri
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