January 20th, 2013 at 8:29:54 AM
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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:
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 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 |
---|---|---|---|
2 | 0.027 | -1 | -0.02777 |
3 | 0.055 | -1 | -0.05555 |
7 | 0.166 | +1 | -0.16666 |
11 | 0.055 | +1 | -0.05555 |
12 | 0.027 | -1 | -0.02777 |
all other | 0.67 | -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 )
January 20th, 2013 at 8:52:19 AM
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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)
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
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)
Event | Freq. | Line Bet | Total Line | Odds Bet | Total Odds | Line Pay | Odds Pay |
---|---|---|---|---|---|---|---|
Natural 7 | 330 | 1 | 330 | 0 | 0 | 330 | 0 |
Natural 11 | 110 | 1 | 1100 | 0 | 0 | 110 | 0 |
Craps | 220 | 1 | 220 | 0 | 0 | -220 | 0 |
4 Made | 55 | 1 | 55 | 0 | 0 | 55 | 0 |
4 Not | 110 | 1 | 110 | 0 | 0 | -110 | 0 |
5 Made | 88 | 1 | 88 | 0 | 0 | 88 | 0 |
5 Not | 132 | 1 | 132 | 0 | 0 | -132 | 0 |
6 Made | 125 | 1 | 125 | 0 | 0 | 125 | 0 |
6 Not | 150 | 1 | 150 | 0 | 0 | -150 | 0 |
8 Made | 125 | 1 | 125 | 0 | 0 | 125 | 0 |
8 Not | 150 | 1 | 150 | 0 | 0 | -150 | 0 |
9 Made | 88 | 1 | 88 | 0 | 0 | 88 | 0 |
9 Not | 132 | 1 | 132 | 0 | 0 | -132 | 0 |
10 Made | 55 | 1 | 55 | 0 | 0 | 55 | 0 |
10 Not | 110 | 1 | 110 | 0 | 0 | -110 | 0 |
Totals - | 1980 | xxx | 1,980 | xxx | 0 | -28 | 0 |
1,980 | -0.014141414 | -28 | |||||
handle | house edge | net 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)
January 20th, 2013 at 9:44:11 AM
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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!
Thanks for the help!
I run Easy Vegas ( https://easy.vegas )