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No Beard
06 Nov 10 12:27
Joined:
Date Joined: 08 Jul 03
| Topic/replies: 178 | Blogger: No Beard's blog
Tennis probability problem:

How many different possible paths within a set are there til the end of a set?

For example:

             
Game:       1   2   3   4   5   6   7
Player A:   W   W   W   W   W   W
Player B:   L   L   L   L   L   L

So, there are 2 possible pathways for 6-0. But how many are there total possibilities?


Cheers guys
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Report No Beard • November 6, 2010 11:29 AM GMT
Would it be   2+2^2+2^3+2^4+2^5+2^6+2^7  ?
Report The Betfairy • November 6, 2010 1:02 PM GMT
Is the answer: Don't worry, just courtside?
Report [x] These checkboxes suck • November 6, 2010 4:13 PM GMT
I make it 2(6C6 + 7C6 + 8C6 + 9C6 + 10C6 + 11C6 + 12C6)
= 2(1 + 7 + 28 + 84 + 210 + 924)
= 2508
Report [x] These checkboxes suck • November 6, 2010 4:13 PM GMT
sorry meant 2(6C6 + 7C6 + 8C6 + 9C6 + 10C6 + 12C6)
Report jt45 • November 6, 2010 5:27 PM GMT
I don't agree TCS.

Your figures give all the number of 'folds of 6' from 6,7,8,9,10,11 & 12 games respectively for each player. Therefore, I don't think that you've fully accounted for tennis' scoring structure. 

For example your figure for a player winning a set 6-1 is 7 (7!/(6!*1!)). Unfortunately that figure would include the 'fold' where a player went 6-0 up and the opposing player then won 1 game.

e.g. There are only 6 ways each player could win a set in 7 games (6-1); LWWWWWW, WLWWWWW, WWLWWWW, WWWLWWW, WWWWLWW, & WWWWWLW.

Your figure of 7 would also seem to include WWWWWWL, which is not possible under the tennis scoring system.
Report Lay Low • November 6, 2010 5:45 PM GMT
Pretty much what I was thinking
only outcomes are;
6-0 =  6 matches
6-1 =  7 matches with the final match being a "W"
6-2 =  8 matches with the final match being a "W"
6-3 =  9 matches with the final match being a "W"
6-4 =  10 matches with the final match being a "W"
7-5 =  12 matches with the final match being a "W"
7-6 =  13 matches with the final match being a "W"

It should be easy to work out the number of paths for each of these outcomes then add them and double the result.
Report [x] These checkboxes suck • November 7, 2010 1:35 AM GMT
yep agree with you both, needs a little more thought than I first thought!
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