scottuga44
scottuga44
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December 13th, 2014 at 7:54:49 AM permalink
This is a bet I saw two guys make at a poker game. I was trying to figure out how big an edge the one guy had but was unsure how to set it up.

Standard poker deck, all cards are worth the same as in blackjack. Aces are always 11. If the three flop cards equal 21 it's push. How big of an edge does the person have who is betting the flop will be 22 or greater?
RS
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December 13th, 2014 at 8:05:50 AM permalink
Are they both betting the same amount (1:1)? If that is the case, in which case I'll assume it is, I'm going to see if I can figure out the advantage/disadvantage. Chances are I won't be able to, at least not right now. But I'll report back (soon?) with what I think the advantage is.

I'm going to assume there is "no information", ie: The first 3 cards can be any 3 cards of a normal 52-card deck, without the information of what my 2 card hand is.


edit: actually nvm i don't want to figure this out. but it is an interesting proposition. without doing any math, i'd say the person betting 3 cards is greater than 21 has a very strong edge.
scottuga44
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December 13th, 2014 at 8:08:17 AM permalink
Bet is 1:1, we have no other information other than its a standard 52 card deck
ThatDonGuy
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December 13th, 2014 at 8:27:20 AM permalink
Here's what I get:
ValueFlopsWinsLosses
64220960
724220724
8482202428
9922193276
1013621796168
1120021596304
1226821328504
1335220976772
14512204641124
15740197241636
16896188282376
171080177483272
181196165524352
191336152165548
201408138086884
211508123008292
221800105009800
231856864411600
241652699213456
251472552015108
261264425616580
271108314817844
28920222818952
29784144419872
3084060420656
3150410021496
3296422000
334022096

If the push number is 22 or less, then it is a good bet; if it is 23 or more , then it is a bad bet.

This assumes all aces are 11, as opposed to "the first ace is 11, but the second and third aces are 1".
RS
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December 13th, 2014 at 8:59:09 AM permalink
Quote: ThatDonGuy

Here's what I get:

ValueFlopsWinsLosses
64220960
724220724
8482202428
9922193276
1013621796168
1120021596304
1226821328504
1335220976772
14512204641124
15740197241636
16896188282376
171080177483272
181196165524352
191336152165548
201408138086884
211508123008292
221800105009800
231856864411600
241652699213456
251472552015108
261264425616580
271108314817844
28920222818952
29784144419872
3084060420656
3150410021496
3296422000
334022096

If the push number is 22 or less, then it is a good bet; if it is 23 or more , then it is a bad bet.

This assumes all aces are 11, as opposed to "the first ace is 11, but the second and third aces are 1".



What about 21 is a push, > 21 wins, and < 21 loses?

How did you come up with your answer, specifically?
ThatDonGuy
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December 13th, 2014 at 9:11:52 AM permalink
Quote: RS

What about 21 is a push, > 21 wins, and < 21 loses?

How did you come up with your answer, specifically?


Of the 22,100 possible three-card flops, 12,300 are higher than 21, 8292 are lower than 21, and 1508 are exactly 21.

I got my numbers through a count of all 22,100 possible three-card flops.
RS
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December 13th, 2014 at 9:21:34 AM permalink
Quote: ThatDonGuy

Of the 22,100 possible three-card flops, 12,300 are higher than 21, 8292 are lower than 21, and 1508 are exactly 21.

I got my numbers through a count of all 22,100 possible three-card flops.



Specifically, though? How'd you figure 22,100 different 3-card flops combinations? How'd you come up with 12,3000 are higher than 21? Surely you didn't write down each combination "2, 2, 2 is 6. 2, 2, 3 is 7. 2, 2, 4 is 8...." and go from there.

I'm not trying to say you're wrong (or right). But I'm genuinely interested in how you came up with those figures.
PeeMcGee
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December 15th, 2014 at 1:45:50 AM permalink
Quote: RS

Specifically, though? How'd you figure 22,100 different 3-card flops combinations? How'd you come up with 12,3000 are higher than 21? Surely you didn't write down each combination "2, 2, 2 is 6. 2, 2, 3 is 7. 2, 2, 4 is 8...." and go from there.

I'm not trying to say you're wrong (or right). But I'm genuinely interested in how you came up with those figures.


Yea, that's what computers are for. Probably the easiest way to solve it.

But you could estimate the answer.

First, total combinations = (52*51*50) / (3*2*1) = 22100

Now let X be the value of any single card.
Then, E[X] = 380/52 = 7.308
And, var[X] = 8.52

So, E[X1+X2+X3] = 7.308*3 = 21.92
cov[Xi,Xj] = -var[X]/(N-1) = -8.52/51 = -0.167
And, var[X1+X2+X3] = var[X1]+var[X2]+var[X3]+2cov[X1,X2]+2cov[X1,X3]+2cov[X2,X3] = (8.52*3) - (6*0.167) = 24.56

Therefore, the standard deviation is...
sd = 24.561/2 = 4.96

Then, the Z-value = (21.5 - 21.92)/4.96 = -0.0847
And P(Z>-0.0847) = 0.534

53.4% of 22100 is 11801

So about 11801 combinations are greater than 21.
Similar process get 8553 combinations less than 21 and 1746 combinations that are 21.

Again, this is just an estimation. ThatDonGuy has the exact solution. Also, I'm a tad rusty on this stuff...I'm not 100% sure if everything I did was legal.
ThatDonGuy
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December 15th, 2014 at 7:08:29 AM permalink
Quote: RS

Specifically, though? How'd you figure 22,100 different 3-card flops combinations? How'd you come up with 12,3000 are higher than 21? Surely you didn't write down each combination "2, 2, 2 is 6. 2, 2, 3 is 7. 2, 2, 4 is 8...." and go from there.

I'm not trying to say you're wrong (or right). But I'm genuinely interested in how you came up with those figures.


There are 52 x 51 x 50 / 6 = 22,100 different flops - 52 possibie cards for the first one; for each of these, 51 possible remaining cards for the second one; for each of these, 50 possible remaining cards for the third one, so that's 52 x 51 x 50, but in a flop, the order doesn't matter (As 2h 3c is the same flop as 2h 3c As), so divide by the six different orders in which three cards can appear.

Here's some "pseudocode" for counting how many of each value there are:

The cards are numbered 0-51; the rank = (the number divided by 4 and rounded down) + 1 (so 1 = Ace, 2 = 2, ..., 13 = King)

FlopCounts[34] is an array where all of the values are initially 0
for (Card1 = 0 to 49):
{
. . . . Rank1 = floor(Card1 / 4) + 1
. . . . if (Rank1 > 9) then Rank1 = 10
. . . . if (Rank1 = 1) then Rank1 = 11
. . . . for (Card2 = Card1 + 1 to 50)
. . . . {
. . . . . . . . Rank2 = floor(Card2 / 4) + 1
. . . . . . . . if (Rank2 > 9) then Rank2 = 10
. . . . . . . . if (Rank2 = 1) then Rank2 = 11
. . . . . . . . for (Card3 = Card2 + 1 to 51)
. . . . . . . . {
. . . . . . . . . . . . Rank3 = floor(Card3 / 4) + 1
. . . . . . . . . . . . if (Rank3 > 9) then Rank3 = 10
. . . . . . . . . . . . if (Rank3 = 1) then Rank3 = 11
. . . . . . . . . . . . FlopValue = Rank1+ Rank2 + Rank3
. . . . . . . . . . . . FlopCounts[FlopValue] = FlopCounts[FlopValue] + 1
. . . . . . . . }
. . . . }
}

When this is done, FlopCounts[N] contains the number of flops where the total is N
It is then a simple matter, for each N, of adding up FlopCounts[3] through FlopCounts[N-1] to determine the number < N, and adding up FlopCounts[N+1] through FlopCounts[33] to determine the number > N.
(Actually, in this case, you can start with FlopCounts[6], as that is the smallest possible flop total if all Aces are 11.)
miplet
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December 15th, 2014 at 9:51:56 AM permalink
Quote: scottuga44

This is a bet I saw two guys make at a poker game. I was trying to figure out how big an edge the one guy had but was unsure how to set it up.

Standard poker deck, all cards are worth the same as in blackjack. Aces are always 11. If the three flop cards equal 21 it's push. How big of an edge does the person have who is betting the flop will be 22 or greater?


The person betting 22 or more has a 18.13574661% edge.

Quote: RS

Specifically, though? How'd you figure 22,100 different 3-card flops combinations? How'd you come up with 12,3000 are higher than 21? Surely you didn't write down each combination "2, 2, 2 is 6. 2, 2, 3 is 7. 2, 2, 4 is 8...." and go from there.

I'm not trying to say you're wrong (or right). But I'm genuinely interested in how you came up with those figures.


I used a spread sheet.
“Man Babes” #AxelFabulous
mickeycrimm
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December 15th, 2014 at 11:05:05 AM permalink
There is also the hustle of betting a guy that a 6, 7, or 8 will come on flop which I put at about 60%.
"Quit trying your luck and start trying your skill." Mickey Crimm
Avincow
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December 15th, 2014 at 11:12:43 AM permalink
Question: so do people just make little side bets in poker from time to time? Does the house frown upon this type of activity? I've never seen any of these types of bets being made when I play poker. Sounds fun though. Do you think it would be impolite to make such a bet with another player knowing that you have the advantage?
ChesterDog
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December 15th, 2014 at 11:15:55 AM permalink
Quote: scottuga44

This is a bet I saw two guys make at a poker game. I was trying to figure out how big an edge the one guy had but was unsure how to set it up.

Standard poker deck, all cards are worth the same as in blackjack. Aces are always 11. If the three flop cards equal 21 it's push. How big of an edge does the person have who is betting the flop will be 22 or greater?



I get 18.13574661%, too.


Flop Pays Permutations
6 -1 24
7 -1 144
8 -1 288
9 -1 552
10 -1 816
11 -1 1200
12 -1 1608
13 -1 2112
14 -1 3072
15 -1 4440
16 -1 5376
17 -1 6480
18 -1 7176
19 -1 8016
20 -1 8448
21 0 9048
22 1 10800
23 1 11136
24 1 9912
25 1 8832
26 1 7584
27 1 6648
28 1 5520
29 1 4704
30 1 5040
31 1 3024
32 1 576
33 1 24
Total 132600
aladyat42
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December 15th, 2014 at 11:47:54 AM permalink
Quote: mickeycrimm

There is also the hustle of betting a guy that a 6, 7, or 8 will come on flop which I put at about 60%.




I think you were about 4.71%


high Mickey, or 3 sheets to the wind ?
miplet
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December 15th, 2014 at 12:42:39 PM permalink
Quote: mickeycrimm

There is also the hustle of betting a guy that a 6, 7, or 8 will come on flop which I put at about 60%.



Second question from Ask the Wiz 196
Quote: question

Playing last night, one of the players, an old crafty scruffy aggressive player, was challenging the table to make even money side bets on the flop. This old curmudgeon was betting that one of the three cards on the flop would be either an ace, deuce, or jack (sometimes he would change the 3 identifiable cards). What are the odds of this bet? Your sage wisdom would be greatly appreciated.


Quote: answer

Before any cards are seen, the probability of any three ranks not appearing on the flop are combin(40,3)/combin(52,3) = 9880/22100 = 44.71%. So this guy had a 10.59% advantage.

“Man Babes” #AxelFabulous
aladyat42
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December 15th, 2014 at 12:46:48 PM permalink
So the odds of a 6 7or 8 appearing is 55.29. Mickey, who was right and who was wrong ?
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