h file or directory LynnBlakeGolf Forums - View Single Post - Fun Probability problem
View Single Post
  #5  
Old 02-19-2007, 07:37 AM
Toolish Toolish is offline
Senior Member
 
Join Date: Aug 2005
Posts: 139
Originally Posted by Mathew View Post
The fact is that your chances of chosing the goat is 2 in 3 and the car 1 in 3.

If you choose either goat, the other goat will be eliminated and if you then choose to switch - you will get the car. There is 2 in 3 chance of this occuring

If you initially pick the car, switching will come out incorrect. There is a 1 in 3 chance of this occuring.

Therefore switching doubles your chances from 1 in 3 into 2 in 3.

--------

Still confused? This is far more apparent of a case of 100 doors. Your chance of getting the first one right is 1 in 100. If once you had selected your door, 98 were then opened and eliminated, it would be far more likely that the other door left would be the correct door. The correct strategy would then be to switch....

Wrong as far as i see it.

They are mutually exclusive events...the outcome of the first goat being revealed does not change the second result...you have a 50% chance of being correct either way once the other doors are revealed.

With your 100 door example, once the other 98 are revealed you are still left with a 50% chance of either door being right...the fact that incorrect doors have been removed from the equation means nothing...in choosing between the final 2 doors switch or stay means nothing, the door you initially chose becomes irrelevant.
Reply With Quote