[dba-Tech] The Three Doors Problem

Scott Marcus marcus at tsstech.com
Fri Aug 26 10:02:59 CDT 2005


John,

The host's intentions have nothing to do with the math. The fact is that
the host revealed a non-winning door. Therefore your odds of winning are
2/3 if you switch.

Scott Marcus
IT Programmer
TSS Technologies Inc.
www.tss.com


-----Original Message-----
From: dba-tech-bounces at databaseadvisors.com
[mailto:dba-tech-bounces at databaseadvisors.com] On Behalf Of John W.
Colby
Sent: Friday, August 26, 2005 10:52 AM
To: 'Discussion of Hardware and Software issues'
Subject: RE: [dba-Tech] The Three Doors Problem

It does indeed state that, what it does NOT state is that the host
INTENTIONALLY PICKED a non-winning door.

>I am the host of a TV program and you are the guest. This is the deal: 

>there are 3 doors. Behind one of them is $100 million. Behind the other
two
are a dead catfish and a dead pickerel respectively. 

>I invite you to select a door. You choose any one of the three: call it
x.

>I open another door, and say, Had you selected door y, you would have
won a
dead catfish.

That is the original message, word for word, as stated in Arthur's
email.

The last sentence is the crux of the matter...

>I open another door, and say, Had you selected door y, you would have
won a
dead catfish.

Had he said:

"I intentionally pick a door that is a loser and say..."

THEN the solution being discussed is indeed valid.  It his use of the
knowledge he has that is the issue. 

If the host flips a coin, and uses the result of the coin toss to pick
one
of the other doors, then you are back to 50/50.  He is not telling you
anything, he is just eliminating a door, that just happens to be a
loser.

John W. Colby
www.ColbyConsulting.com 

Contribute your unused CPU cycles to a good cause:
http://folding.stanford.edu/

-----Original Message-----
From: dba-tech-bounces at databaseadvisors.com
[mailto:dba-tech-bounces at databaseadvisors.com] On Behalf Of Scott Marcus
Sent: Friday, August 26, 2005 10:36 AM
To: Discussion of Hardware and Software issues
Subject: RE: [dba-Tech] The Three Doors Problem


John,

The problem was stated originally that the host revealed a non-winning
door.

Scott Marcus
IT Programmer
TSS Technologies Inc.
www.tss.com
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