Author: Rolf Tueschen
Date: 05:43:06 09/27/02
Go up one level in this thread
On September 27, 2002 at 08:22:06, Sune Fischer wrote: >On September 27, 2002 at 08:14:28, Gerrit Reubold wrote: > >>Hi Sune, >> >>On September 26, 2002 at 14:47:32, Sune Fischer wrote: >> >>>On September 25, 2002 at 15:06:58, John Merlino wrote: >>>>correct if you switch. The "host" has nothing to do with it, because he/she MUST >>>>choose a door to open. >> >> >>>Not entirely correct, the host has got something to do with it. The host must >>>KNOW which door hides the car. It is vital that he doesn't open a door to a goat >>>by shear luck, because in that case you do not get that 2/3 odds. >>> >> >>I disagree, I am sure it doesn't matter whether the host opens a door (with a >>goat) KNOWING where the car is or by SHEAR LUCK. The candidate should switch in >>either case, thus improving his winning odds from 1/3 to 2/3. Of course, if the >>host doesn't know and opens the door with the car (accidently), the game is over >>:-) > >Ok, well at least we agree that if he KNOWS he should switch. > >So suppose the host doesn't know, and the host opens a door to a goat. > >What does this tell us? >Well, since he didn't know, it means he either had a 50% probability of opening >to a goat, or a 100% probability. > >He gets 100% probability if we are sitting on the car, and he gets 50% if the >car is behind the one of the doors he had to choose from. > >The odds of picking a goat if you have 100% probability is higher than if you >only have 50% (obviously), okay? > >Thus we now know it is more probable that we did pick the door with the car, >because the host was so lucky to pick one with a goat, which is a lot more >proabable if he had nothing but goats to choose from. > Err, Sune, is it true that if I, err, sit in two cars, that I should have two keys? The problem get's more complicated than expected, I must apologize, but what would be your verdict? :) Rolf Tueschen >-S. > >>Greetings, >>Gerrit
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