[GERMAN] "ziegenproblem"
Gerhard Häring
gerhard at bigfoot.de
Thu Mar 7 23:08:38 EST 2002
Peter Hansen wrote in comp.lang.python:
> Paul Rubin wrote:
>>
>> stefan antoni <sasoft at gmx.de> writes:
>> > sorry that i won't be able to explain this in english, i don't know the
>> > name of this problem in english, and the website which is about this
>> > problem is also in german.
>>
>> Usually we call it the "Monty Hall problem". Monty Hall was the host
>> of a TV game show where he actually played that game (put a prize behind
>> one of three doors, etc).
>
> See also http://c2.com/cgi/wiki?MontyHallProblem for full discussion.
Most of the explanations are too complicated IMHO. This is how I
finally understood the problem:
Your original choice has a chance of 1/3 to win the prize. This
doesn't change no matter what the moderator will do. Consequenetly,
the chance that the prize is hidden behind one of the two remaining
doors is 2/3.
So, now, the moderator opens one of the goat doors, but not yours.
Your original choice still has a chance of 1/3 to be correct, but the
two thirds for the other two doors now only apply to one door. That's
why switching doors is smart.
A little ASCII art :)
After your original choice:
+------+ +------+ +------+
| ? | | ? | | ? |
+------+ +------+ +------+
your choice
\-------+--------/ chance to win:
| 1/3
chance to win: 2/3
+------+ +------+ +------+
| goat | | ? | | ? |
+------+ +------+ +------+
chance to chance to
win: 2/3 win: 1/3
Gerhard
--
mail: gerhard <at> bigfoot <dot> de registered Linux user #64239
web: http://www.cs.fhm.edu/~ifw00065/ OpenPGP public key id AD24C930
public key fingerprint: 3FCC 8700 3012 0A9E B0C9 3667 814B 9CAA AD24 C930
reduce(lambda x,y:x+y,map(lambda x:chr(ord(x)^42),tuple('zS^BED\nX_FOY\x0b')))
More information about the Python-list
mailing list