View Single Post
  #16 (permalink)  
Old 03-21-2008, 12:53 PM
Contra_Mundum's Avatar
Contra_Mundum Contra_Mundum is offline.
"da wabbit"
 
Join Date: Feb 2004
Location: CentralLakeMI
Posts: 3,786
Thanks: 7
Thanked 962 Times in 371 Posts
Quote:
Originally Posted by CalvinandHodges View Post
Suppose you're on a game show, and you're given the choice of three doors: Behind one door is a car; behind the others, goats. You pick a door, say No. 1, and the host, who knows what's behind the doors, opens another door, say No. 3, which has a goat. He then says to you, "Do you want to pick door No. 2?" Is it to your advantage to switch your choice?

In other words: What is the probability that if you switch you will win?
I also think the math supports switching. The point of all of these games is that they are counter-intuitive, our "basic ideas" are being manipulated by the addition of a variable or two.

At first pick, you probably guessed wrong. That's just a fact. You only had a 1/3 probability of being right, 2/3 of being wrong. You probably have a goat. This is the fact that is missed when, in the 2nd place, you are given a supposedly 50-50 choice.

Then, the FALSE alternative is removed. So, switch. Your odds are slightly BETTER than 1/2 to get the car, rather than lose it, by switching.

Add to it this: if the hosts want to "create a winner" (say its been a bad day for winners), and you get it RIGHT the first time, maybe they just open the door for you and congratulate you on your pick. By giving you a "second choice" they may be hoping you will get the car, but still making a game of it. Can't leave out the "entertainment" factor...
__________________
Rev. Bruce G. Buchanan
ChainOLakes Presbyterian Church, CentralLake, MI

Made both Lord and Christ--Jesus, the Destroyer
Acts 2:36 - 1 Cor. 10:9-10 & 15:22-26 - Hebrews 2:9-15 - 1 John 3:8 - James 4:12

When posting friends, kindly bear those words of earthly wisdom in mind:

Oh, that God the gift would give us
To see ourselves as others see us.
--Robert Burns, 1786 (modernized) ♦ ♦ ♦ ♦ ♦ ♦ ♦ ♦ ♦ ♦ Click to get: Board Rules -- Signature Requirements -- Suggestions? --
Reply With Quote
The Following 2 Users Say Thank You to Contra_Mundum For This Useful Post:
CalvinandHodges (03-21-2008), Seb (03-21-2008)