Actuarial Outpost how to calculate your odds fast on Flop
 Register Blogs Wiki FAQ Calendar Search Today's Posts Mark Forums Read
 FlashChat Actuarial Discussion Preliminary Exams CAS/SOA Exams Cyberchat Around the World Suggestions

ACTUARIAL SALARY SURVEYS - From Entry to Fellow

#1
11-01-2006, 02:38 PM
 freeman Member Join Date: Jun 2005 Posts: 681
how to calculate your odds fast on Flop

I published this table in my blog (sorry if you cannot read Chinese). On flop, there are two cards to come, assume you are going to the river and all the 47 cards are unknow to you, you have N outs, then the accurate percentage you win is AcuP=100x[1- ((47-N)/47)x((46-N)/46)]. it is not an easy work to complete the calculation in your mind in a moment. However, I got a easy way to do it in just 1 second. My approximate formula is

EstP= 4xN - r

where r is:
0 for N<9,
1 for N=9, and
N-9 for N>9.

In the table, first column is number of outs, 2nd column is the AcuP, 3rd column is the EstP, and the next untitled column is the difference. you can see that they fit very well, all within 1% for N<20. but it is very rare that N>20.

In the Green Area, I give some modification for 46 and 45 unknow cards. In case you have very good guess on your opponent's one or two cards, or in casino some cards are accidently exposed, then you accually have 46 or 45 unknow cards. The listed number are the real probability, you can see that it is easy to memrize them: if you know one card(46 unknow), then add 1 to EstP, if you know 2 cards, then add 2 to EstP.

Last edited by freeman; 11-01-2006 at 02:41 PM..
#2
11-01-2006, 02:52 PM
 tesla_styx Member Join Date: Nov 2001 Posts: 1,679

Cool estimation! thanks for sharing.
#3
11-01-2006, 02:52 PM
 DblDownTrent Member Join Date: Oct 2003 Location: in a van, down by the river Favorite beer: Ice Cold Posts: 5,231

is it possible to be behind on the flop and have 20+ outs? haven't really thought about it that much, but am curious.

TdJd vs 2c2s on a 8d9d9c board?

any 7,8,T,J,Q, any diamond.
#4
11-01-2006, 02:56 PM
 Judge Dredd Member SOA AAA Join Date: May 2005 Location: Mega-City One Favorite beer: Bud Select Posts: 15,496

Quote:
 Originally Posted by DblDownTrent is it possible to be behind on the flop and have 20+ outs? haven't really thought about it that much, but am curious. TdJd vs 2c2s on a 8d9d9c board? any 7,8,T,J,Q, any diamond.
if you have 20 outs, 40 of the 45 cards are yours.
__________________
GO Ohio State!!!!!!!!!!!

#5
11-01-2006, 02:57 PM
 hardinda Member Join Date: Nov 2003 Location: some \$0 SNG Favorite beer: Yes Posts: 14,179

After the turn change it to 2xN-r ... good to go for your final card. I usually use N with 8 instead of 9. Apoc pointed this out awhile back I think.
#6
11-01-2006, 02:58 PM
 Sotally Tober Member Join Date: Apr 2002 Location: Cincinnati Favorite beer: Bell's Hopslam Posts: 15,469

Quote:
Originally Posted by Judge Dredd
Quote:
 Originally Posted by DblDownTrent is it possible to be behind on the flop and have 20+ outs? haven't really thought about it that much, but am curious. TdJd vs 2c2s on a 8d9d9c board? any 7,8,T,J,Q, any diamond.
if you have 20 outs, 40 of the 45 cards are yours.
#7
11-01-2006, 02:58 PM
 hardinda Member Join Date: Nov 2003 Location: some \$0 SNG Favorite beer: Yes Posts: 14,179

DDT ... (4x20) - (20-9) = 69% ... so, that answer is NO
#8
11-01-2006, 03:00 PM
 Arachn Member Join Date: Jun 2005 Location: The AO, duh Studying for Omaha 101 Posts: 6,710

Actually 45 unknown is very useful - Omaha
__________________
hardinda [observer]: where's superman?

JPette333 [observer]: spidurman is da man
JPette333 [observer]: **** superman
#9
11-01-2006, 03:03 PM
 win diesel Member SOA Join Date: Nov 2002 Location: Some 500 FPP Step1 Favorite beer: lol beer ... ketel1 please....k thks Posts: 29,891

I'm pretty fooking dumb. I need to play better. But why not just use the rule of 4 (flop) and 2 (turn)?
#10
11-01-2006, 03:06 PM
 Judge Dredd Member SOA AAA Join Date: May 2005 Location: Mega-City One Favorite beer: Bud Select Posts: 15,496

Quote:
 Originally Posted by win diesel I'm pretty fooking dumb. I need to play better. But why not just use the rule of 4 (flop) and 2 (turn)?
thats good enough win. There is no need to get it down to the 0.000X% precision unless you have xray vision and know exactly what your opponent(s) hold.
__________________
GO Ohio State!!!!!!!!!!!

 Thread Tools Display Modes Linear Mode

 Posting Rules You may not post new threads You may not post replies You may not post attachments You may not edit your posts BB code is On Smilies are On [IMG] code is On HTML code is Off

All times are GMT -4. The time now is 04:32 AM.

 -- Default Style - Fluid Width ---- Default Style - Fixed Width ---- Old Default Style ---- Easy on the eyes ---- Smooth Darkness ---- Chestnut ---- Apple-ish Style ---- If Apples were blue ---- If Apples were green ---- If Apples were purple ---- Halloween 2007 ---- B&W ---- Halloween ---- AO Christmas Theme ---- Turkey Day Theme ---- AO 2007 beta ---- 4th Of July Contact Us - Actuarial Outpost - Archive - Privacy Statement - Top