[Search for users] [Overall Top Noters] [List of all Conferences] [Download this site]

Conference rusure::math

Title:Mathematics at DEC
Moderator:RUSURE::EDP
Created:Mon Feb 03 1986
Last Modified:Fri Jun 06 1997
Last Successful Update:Fri Jun 06 1997
Number of topics:2083
Total number of notes:14613

603.0. "world series probability" by RAYNAL::OSMAN (and silos to fill before I feep, and silos to fill before I feep) Mon Oct 27 1986 13:20

Consider a sporting event, such as the world series, in which the
first team to win 4 games is the champion.

Suppose the teams are of equal strength.  What is the probability
that the match lasts 7 games ?

How about the general question:  One team has a probability of P
of winning any given game.  What is the probability, M (stands for "max"),
that a "best of L" series runs the full L games ?

/Eric
T.RTitleUserPersonal
Name
DateLines
603.16-game series is much more commonMODEL::YARBROUGHMon Oct 27 1986 14:037
>Suppose the teams are of equal strength.  What is the probability
>that the match lasts 7 games ?

The series will go to 7 games only if the first 6 are split 3-3, which will 
happen
	6!/(3!*3!)/2^6 = 5/16
of the time. A six-game series will happen 30/64 of the time.
603.26 and 7 games are equally likelyVINO::JMUNZERMon Oct 27 1986 15:4014
     For either a six or seven game series, the first five games must be
     split 3 - 2.  then there are equal chances of 

	4 - 2 (six game series)
    and
	3 - 3 (seven game series).

    But the formula of .1 looks good:
    
    	  2n
    	(    )   x   p ^ n   x   (1 - p) ^ n
    	   n
    
    John
603.3307 echoesVINO::JMUNZERMon Dec 29 1986 19:256
What fraction of those World Series in which the American League didn't get
shut out should have lasted seven games?
    
(Assuming even chances of winning for all teams in all Series.)
    
John
603.4another lookESTORE::ROOSThu Jan 15 1987 16:0819
    
    
    refering to .1
    
    The probability that the series will end in exactly 6 games (assuming
    equal strength) is 5/16.
    
    As a matter of fact, the following is true:
    
         Number of games     Probability
        =================   =============
               4                 2/16
               5                 4/16
               6                 5/16
               7                 5/16
    
     Also, the expected number of games is 5 and 13/16.
    
    
603.5exitCIVAGE::BUCHANANTue Jul 23 1991 22:575
    s'pose that the two teams aren't equally matched?   How does the
    probability of a 6-game tournament vary?   A 5-game tournament?
    What would your intuition say?
    
    Andrew.