MichaelBluejay
MichaelBluejay
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Joined: Sep 17, 2010
January 20th, 2013 at 8:29:54 AM permalink
I hate advertising how poor my math skills are, but this forum is the best place to get help with this kind of problem.

I know how the Wizard calculates the house edge on the craps pass line, but I want to do it in table format so I can figure what the house (or player) edge would be if the shooter could influence the probability of getting a 7 on the come-out. The first step is to table-ize the figures assuming fair odds. Doing that, I get:

Throw Prob. Pay EV
20.027-1-0.02777
30.055-1-0.05555
70.166+1-0.16666
110.055+1-0.05555
120.027-1-0.02777
all other0.67-0.458-0.30572
-0.19


I figured the "all other" pay by using the 9648/35640 chance of winning a point once it's been established (from the Wizard's craps appendix). -1 x 9468/35640 + 1 x 26172/35640.

Anyway, my result of a house edge of -0.19 doesn't come close to the true house edge of -1.41%. How did I err?
I run Easy Vegas ( https://easy.vegas )
miplet
miplet
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Joined: Dec 1, 2009
January 20th, 2013 at 8:46:44 AM permalink
You will lose once the point is established 14112/35640
I have a copy of my custom craps ev in google docs here
“Man Babes” #AxelFabulous
7craps
7craps
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January 20th, 2013 at 8:52:19 AM permalink
also a table from WinCraps


The fraction, instead of -0.0141, should sum to -28/1980 (-7/495)

For those that do not want to deal with fractions and decimals
Here is the perfect 1980 table
(all fractions are multiplied by 55/55
example: 6/36 for the 7 becomes 6/36 * 55/55 = 330/1980)

EventFreq.Line BetTotal LineOdds BetTotal OddsLine PayOdds Pay
Natural 73301330003300
Natural 1111011100001100
Craps220122000-2200
4 Made5515500550
4 Not110111000-1100
5 Made8818800880
5 Not132113200-1320
6 Made1251125001250
6 Not150115000-1500
8 Made1251125001250
8 Not150115000-1500
9 Made8818800880
9 Not132113200-1320
10 Made5515500550
10 Not110111000-1100
Totals -1980xxx1,980xxx0-280
     1,980-0.014141414-28
     handlehouse edgenet loss

HA = -28/1980 (-7/495)
examples:
Probability of a come out roll 7 is 330/1980 (1/6)
Probability of a come out roll decision is (330+110+220)/1980 = 1/3
winsome johnny (not Win some johnny)
MichaelBluejay
MichaelBluejay
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Joined: Sep 17, 2010
January 20th, 2013 at 9:44:11 AM permalink
Okay, my mistake was when the Wizard wrote, "The probability of establishing a point and then winning...", I read that as, "The probability of winning a point that's established."

Thanks for the help!
I run Easy Vegas ( https://easy.vegas )
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