steve2929
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August 3rd, 2011 at 9:11:25 AM permalink
What are the odds of throwing all 6 point numbers before a 7? I can't find a proof, I get a different result depending on what sequence the numbers are rolled. need help
DJTeddyBear
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August 3rd, 2011 at 10:19:28 AM permalink
More info is needed.

Do you mean before ANY 7, or just before a 7-out?

Is it OK to hit numbers repeatedly? Is it OK to hit 2, 3, 11, 12?
I invented a few casino games. Info: http://www.DaveMillerGaming.com/ ————————————————————————————————————— Superstitions are silly, irrational, childish rituals, born out of fear of the unknown. But how much does it cost to knock on wood? 😁
Wizard
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August 3rd, 2011 at 10:34:35 AM permalink
He probably means winning the Fire Bet, which has been discussed before. I indicate the answer in my blackjack appendix 4.
"My life is spent in one long effort to escape from the commonplace of existence. These little problems help me to do so." -- Sherlock Holmes
steve2929
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August 3rd, 2011 at 10:51:20 AM permalink
yes, any 7. its a prop bet. 2,3,11,12 and repeats are stand offs.
Alan
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August 3rd, 2011 at 10:53:38 AM permalink
Quote: Wizard

He probably means winning the Fire Bet, which has been discussed before. I indicate the answer in my blackjack appendix 4.



craps Wiz
DJTeddyBear
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August 3rd, 2011 at 11:25:30 AM permalink
I'm sure I'm over-simplifying it, but I kinda think the answer is:

( ( 3/36 ) * ( 4/36 ) * ( 5/36 ) * ( 5/36 ) * ( 4/36 ) * ( 3/36 ) ) / ( 6/36 ) = 0.0000099229
I invented a few casino games. Info: http://www.DaveMillerGaming.com/ ————————————————————————————————————— Superstitions are silly, irrational, childish rituals, born out of fear of the unknown. But how much does it cost to knock on wood? 😁
boymimbo
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August 3rd, 2011 at 11:32:16 AM permalink
Assuming that the first roll includes a non-come out roll?

My brute force method gets 0.062168. Is there a mathematical way that's easier.

Any one point number before a 7 is 24/30 = .8
Any two different point numbers before a 7 is .614017
Any three different point numbers before a 7 is .443960
Any four different point numbers before a 7 is .292429
Any five different point numbers before a 7 is .163184
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jc2286
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August 3rd, 2011 at 1:16:46 PM permalink
The odds of hitting X before 7:

4 - 1/3
5 - 2/5
6 - 5/11
8 - 5/11
9 - 2/5
10 - 1/3

The odds of hitting them all before a 7 would be the product of those probabilities = 0.3673%
boymimbo
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August 3rd, 2011 at 2:33:54 PM permalink
I kind of thought of that approach but don't agree with it. The odds of throwing a 7 is always 1/6. The odds of throwing n before 7 is expressed as n/(n+6) where n is the number of dice probabilties.

If you think about a pyramid (D4), what is the probability of hitting a 1, 2, and 3 before a 4? The odds of hitting x before 4 is:

1: 1/2
2: 1/2
3: 1/2

Is the odds therefore of hitting 1, 2 and 3 before a 4: 1/8.

No. The experiment starts when a 1, 2, 3 is rolled.

What are the odds, that a different one of the 3 numbers is thrown before a 4. Well it's 2/3rds as there are only three other possibilities as the original number thrown is discarded.

So the odds of 1-2, 1-3, or 2-3 are 1/3 x 2/3 + 1/3 x 2/3 + 1/3 x 2/3 = 6/9

What are the odds then of getting the 3rd digit before the 4? Well it's 1 half as there is one way of getting the 3rd number and 1 way of getting the 4.

6/9 x 1/2 = 6/18 = 1/3.

So, the odds of hitting the 1,2, and 3 before the 4 is 1/3, not 1/8th.
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steve2929
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August 3rd, 2011 at 3:08:23 PM permalink
If the point numbers appear in this order 4,5,6,8,9,10 I get this answer:
24/30 (6 stand offs,6 losses, 24 wins)
x 21/27 (9 stand offs,6 losses, 21 wins)
x 17/23 (13 stand offs,6 losses, 17 wins)
x 12/18 (18 stand offs, 6 losses, 12 wins)
x 7/13 (23 stand offs, 6 losses, 7 wins)
x 3/9 (27 stand offs, 6 losses, 3 wins) = 1/18.171519 or 17.17 to 1

But if the order is 6,8,5,9,4,10 the answer becomes:
24/30
x 19/25
x 14/20
x 10/16
x 6/12
x 3/9 =1/22.556391 or 21.57 to 1

Am I missing something or is it just a matter of taking the average of all the combinations?
boymimbo
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August 3rd, 2011 at 3:22:37 PM permalink
You have the right idea but you have to take all possibilities into account and add them together. Something like that.
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matilda
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August 3rd, 2011 at 3:41:34 PM permalink
Is this what the question is? Quote from ask the Wiz - craps

The Grand Victoria Casino in Elgin, Illinois offers a promotion called "Craps for Cash." A shooter wins a $4,000 cash bonus for making all six points on the same hand. All that's required is a bet on the pass line. How does this affect the house edge on this particular game? – John B. from Riverside, Illinois
The probability of making all six points is 1 in 6156. So the value of this to the shooter is $4000/6156 = 64.98 cents. As long as the shooter bets $45 or less on the pass line, and nothing else except the odds, he will have an advantage. April 12, 2007
steve2929
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August 3rd, 2011 at 3:54:12 PM permalink
The question is simply this:
If a man wants to bet that he can shoot all 6 points before a 7 what single price could he accept to know whether hes getting the best or the worst of the proposition?
There must be a mathematical proof!
teddys
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August 3rd, 2011 at 4:17:20 PM permalink
Anything less than 6156:1 = bad bet. Anything more than 6156:1 = good bet.
"Dice, verily, are armed with goads and driving-hooks, deceiving and tormenting, causing grievous woe." -Rig Veda 10.34.4
jc2286
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August 3rd, 2011 at 6:43:49 PM permalink
Quote: boymimbo

I kind of thought of that approach but don't agree with it. The odds of throwing a 7 is always 1/6. The odds of throwing n before 7 is expressed as n/(n+6) where n is the number of dice probabilties.

If you think about a pyramid (D4), what is the probability of hitting a 1, 2, and 3 before a 4? The odds of hitting x before 4 is:

1: 1/2
2: 1/2
3: 1/2

Is the odds therefore of hitting 1, 2 and 3 before a 4: 1/8.

No. The experiment starts when a 1, 2, 3 is rolled.

What are the odds, that a different one of the 3 numbers is thrown before a 4. Well it's 2/3rds as there are only three other possibilities as the original number thrown is discarded.

So the odds of 1-2, 1-3, or 2-3 are 1/3 x 2/3 + 1/3 x 2/3 + 1/3 x 2/3 = 6/9

What are the odds then of getting the 3rd digit before the 4? Well it's 1 half as there is one way of getting the 3rd number and 1 way of getting the 4.

6/9 x 1/2 = 6/18 = 1/3.

So, the odds of hitting the 1,2, and 3 before the 4 is 1/3, not 1/8th.



Yeah you're right, although I disagree that the experiment starts after the 1st roll. I would say it starts immediately (since it's possible to 7 before hitting any numbers).

So for your example of (D4), it would be P(1st)*P(2nd)*P(3rd) = (3/4)*(2/3)*(1/2) = 1/4

Applying this to the problem at hand gets very complicated, because each number's probability differs, and isn't evenly distributed.
boymimbo
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August 3rd, 2011 at 10:26:39 PM permalink
A seven wouldn't count in craps, as that's the comeout roll. I think my initial answer applies, as I used a brute force method to get the answer.
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FleaStiff
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August 4th, 2011 at 4:27:05 AM permalink
Quote: matilda

The Grand Victoria Casino in Elgin, Illinois offers $4,000 cash for making all six points on the same hand. All that's required is a bet on the pass line.

Gee, all SamsTown in Shreveport, Louisiana offers is a personalized Dice Sharks jacket if you make all six numbers before sevening out. I think they embroider your name on the jacket. I hear its a pretty nifty jacket too, but I'd prefer the four grand!!
dwheatley
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August 4th, 2011 at 6:22:52 AM permalink
I think it's still not clear whether the OP wanted to know:

a) what are the odds of making all 6 points without 7-out and passing the dice (the fire bet), noting you are allowed to throw a 7 on the come out
b) what are the odds of rolling a 4,5,6,8,9,10 before a 7. Forget the rules of craps.

I personally think he wanted b.

In which case, I need one more piece of info: You make the prop bet, what happens if you roll a 7 before any of the other #s? no action, or lose?
Wisdom is the quality that keeps you out of situations where you would otherwise need it
jc2286
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August 4th, 2011 at 7:18:01 AM permalink
Quote: dwheatley

I think it's still not clear whether the OP wanted to know:

a) what are the odds of making all 6 points without 7-out and passing the dice (the fire bet), noting you are allowed to throw a 7 on the come out
b) what are the odds of rolling a 4,5,6,8,9,10 before a 7. Forget the rules of craps.

I personally think he wanted b.

In which case, I need one more piece of info: You make the prop bet, what happens if you roll a 7 before any of the other #s? no action, or lose?



I actually envisioned a 3rd scenario - as if he was just betting across, and wanted to bink each bet before 7-out. That's why I felt the experiment starts right away, because they're typically not "on" until a point is established, at which time a 7 wipes you out (and you still have bets on all 6 numbers to hit).

I think it's clear that the OP's question is unclear.
steve2929
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August 4th, 2011 at 9:02:49 AM permalink
Quote: dwheatley

I think it's still not clear whether the OP wanted to know:

a) what are the odds of making all 6 points without 7-out and passing the dice (the fire bet), noting you are allowed to throw a 7 on the come out
b) what are the odds of rolling a 4,5,6,8,9,10 before a 7. Forget the rules of craps.

I personally think he wanted b.

In which case, I need one more piece of info: You make the prop bet, what happens if you roll a 7 before any of the other #s? no action, or lose?


Thankyou, yes I did mean b. Nothing to do with pass lines, come outs, house edge or anything. A 7 before any of the point numbers is a lose!
guido111
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August 4th, 2011 at 4:09:40 PM permalink
Quote: steve2929

Thankyou, yes I did mean b. Nothing to do with pass lines, come outs, house edge or anything. A 7 before any of the point numbers is a lose!


This is a variation of the "All Bet" that can be found at a few craps tables, where rolling all the numbers B4 a 7 wins.
This also sounds like a variation of the coupon collector problem. With Different probabilities for each coupon and we start over collecting when a 7 rolls.

There are a few scripts and a math example that can calculate the exact odds.
HERE at 2+2 forum

Or a simulation can also come very close.
I know the answer but will let you solve it first your way or using an idea from the above link.

Good Luck
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