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Subject: Re: Why not simulate the tourney instead of coin flipping?

Author: George Tsavdaris

Date: 04:14:19 07/25/03

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On July 24, 2003 at 23:46:50, Tom Kerrigan wrote:

>Given a round robin tournament with 13 participants of equal strength, 5 of
>which are The King:
>
>There's a 14% chance The King would take the top 3 spots.

I don't know for sure***, but i think you are wrong.

Because if the participants have equal strength we can do the following:

If N is the number of all possible classifications of the programs
then N = 13!/5!   as we have five "The King".

If A is the number of all possible classifications where "The King"
has taken the three first places at least (or four of five)
then A = 10!/2! .

Then there is a 100·A/N % chance "The King to be in the 3 (at least)
top spots. So the chance is ~ 3.5 %.

>There's an 11.4% chance of a specific program winning the tournament. (This
>problem is apparently more complex than it seems--I would have guessed a
>1/13=7.6% chance of any given program winning the tournament.)

If B is the number of all possible classifications where a program
(not "The King") wins the tournament then B = 12!/5! .

So there is a 100·B/N % chance a a program (but not "The King")
to win the tournament.
And 100·B/N % = ~ 7.69 %.

For "The King" the possibility to win is C/N where C = 12!/4!.
So 100·C/N % = ~ 38.46 %.
--------------------------------------------
*** = I understand that the above may be wrong, because in a chess
tournament there are no wins-loses but also draws. But the problem
is i don't find a particular reason, this can influence the above
procedure.
--------------------------------------------
>In other words, you should only be slightly less surprised that The King took
>the top 3 spots than if a certain program won a tournament against 12 other
>programs of the same strength. In other words again, it's unlikely that The King
>is the same strength as the other programs.
>



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