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  #1  
Old 12-13-2005, 08:56 PM
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Default Calculating flush odds MY WAY.

10 handed. 10/20 cent limit. u get a5 of spades. 5 calls = pot total 50 cent.

SB bets > 3 folds. You have 4 flush. the odds of ending up with flush at the showdown are according to D. Sklansky are 1.86 : 1.

My version: 20 cards were dealt out preflop. quarter of them or 5 cards will be in the long run spades. u picked up two. Lets assume the other 3 spades will be folded. and two other on the board.

Shoulnt you calculate the chance of flush at the showdown like this:

13 spades total. u have two and three were folded, 2 spades on board. 6 spades in the deck over. so 6/47 * 5/46 + 6/47 * 41/46 + 41/47 * 6/46.

so odds of ending up with flush are 3.09 : 1

discuss...
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  #2  
Old 12-13-2005, 09:42 PM
damaniac damaniac is offline
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Default Re: Calculating flush odds MY WAY.

[ QUOTE ]
Lets assume the other 3 spades will be folded.

[/ QUOTE ]

Let's not.
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  #3  
Old 12-13-2005, 09:57 PM
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Default Re: Calculating flush odds MY WAY.

OMFG. Now I now why even people who read about poker can suck at it. There is a fundamental basic flaw in your analysis. To be honest and not just condescending, it'd be best if you kept looking at it until you figure it out rather than have someone explain it. Maybe that'll help give some grasp on how to approach these things in the future.
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  #4  
Old 12-13-2005, 10:04 PM
RiverDood RiverDood is offline
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Default Re: Calculating flush odds MY WAY.

Your version makes sense only if everyone else's hole cards are gathered up after they are dealt out . . . "de-spaded" . . . cloned for people who want to keep playing their hands -- and then reshuffled into the deck for use in the flop, turn and river.

I try never to play in games where people do that.

It hurts my shot at the flush draw. It lets everyone else know exactly what I'm chasing. And it creates a spooky sense of deja vu that encourages cheating, palming, etc. In short, it's an ugly variant of poker -- and if that's what they play in your town, I'd move away.

In most of the rest of the U.S., we play where the hole cards are not available for the flop/turn/river, regardless of whether people fold them or play them. So in that case, there are only 32 cards left that can go into FTR.

If you want to stick with your assumptions about what's in the 18 hole cards that you don't see, then do the rest of your math with fewer cards left in the deck. (i.e. 6/32 * 5/31 . . . )

You'll end up with something very close to Sklansky's numbers. His are more accurate because you really don't know anything about other people's hole cards. There could be zero spades there or 10 spades there. They are just as unknown to you as the part of the deck that hasn't been dealt yet.
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  #5  
Old 12-13-2005, 10:22 PM
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Default Re: Calculating flush odds MY WAY.

Ok ok, It was just a quick idea on a night of lazyness. Excuse me.
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  #6  
Old 12-13-2005, 10:27 PM
RiverDood RiverDood is offline
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Default Re: Calculating flush odds MY WAY.

Fair enough. We'd be gentler, but poker isn't a gentle game.

Stay sharp and you'll do fine. Don't touch the cards if you're feeling lazy.
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  #7  
Old 12-14-2005, 03:46 AM
EnderW27 EnderW27 is offline
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Default Re: Calculating flush odds MY WAY.

Actually there's at least three mistakes. One is just basic math: There aren't 20 cards dealt out in addition to your hand, there are only 18. That simple flaw should tell you to go check back over every assumption you made.
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  #8  
Old 12-14-2005, 05:38 AM
ThinkQuick ThinkQuick is offline
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Default Re: Calculating flush odds MY WAY.

[ QUOTE ]
If you want to stick with your assumptions about what's in the 18 hole cards that you don't see, then do the rest of your math with fewer cards left in the deck. (i.e. 6/32 * 5/31 . . . )

You'll end up with something very close to Sklansky's numbers. His are more accurate because you really don't know anything about other people's hole cards. There could be zero spades there or 10 spades there. They are just as unknown to you as the part of the deck that hasn't been dealt yet.

[/ QUOTE ]
The first paragraph of this response is great but the second part isn't correct.

To the OP:
You can get the exact same probability if you properly account for the number of spades in the other players hands. You said there would be 3 spades in these 18 cards.
But you need to apply basic probabilities. You are sequestering 4 spades for your hand and the flop, as well as 1 non spade for the flop).

so their hands will contain (9spades/47remaining cards)*18 cards dealt = 3.446 spades within their 18 cards.

Now there are 13spades - 2 in your hand - 3.446 in other hands - 2 on the flop = 5.554 spades remaining

there are 52 - 20 - 3 = 29 cards to come.


5.554 spades in 29 cards = .1915
this is the same as
9 spades in 47 cards = 0.1915

therefore p of getting a flush will be the same in both cases

note that the 9/47 even showed up our calculations.

anyways the point is you can do it 'your' way with the proper math, and it comes out to the same answer. However, the 'D.Sklansky' way is MUCH simpler.
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  #9  
Old 12-14-2005, 10:08 AM
Kurn, son of Mogh Kurn, son of Mogh is offline
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Default Re: Calculating flush odds MY WAY.

If you're going to count the 2 theoretical flush cards that were folded, you have to count the 8 non-flush cards that were folded as well or you math is flawed. The odds remain the same when you account for folded cards, since you must account for *all* folded cards, not just the ones that are outs for you.

Bottom line is, an unseen card is an unseen card is an unseen card.
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  #10  
Old 12-14-2005, 03:30 PM
Xhad Xhad is offline
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Default Re: Calculating flush odds MY WAY.

[ QUOTE ]
If you're going to count the 2 theoretical flush cards that were folded, you have to count the 8 non-flush cards that were folded as well or you math is flawed.

[/ QUOTE ]

It's even worse than that because when you are suited in spades and flop a flush draw, the average number of spades in your opponents' hands will be lower than normal (Conceptual proof: any average distribution of spades should include the case where your opponents' are dealt 10 or 11 of the other spades, but if that happens flopping a flush draw is impossible; but there is no reason to similarly exclude any case when your opponents have less spades than normal. Therefore the average number of spades when you flop a spade draw must be below average)
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