IAchance5
IAchance5
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Joined: May 28, 2010
May 28th, 2010 at 7:50:01 AM permalink
Hi, I love wizard of odds website and it has a lot of great info, but I was reading the craps FAQ on probability and it states:

"On average, during the course of 100 points being established in craps: (1) How many of those would be 4/10, 5/9 or 6/8, (2) During the 100 how many times would each point (4/10, 5/9, 6/8) vs. a 7 being rolled. — Jon Moriarty from Danville, New Hampshire

Of those 100 points established, on average 45.45 would be on a 6 or 8, 40 would be on a 5 or 9, and 33.33 would be on a 4 or 10. You could expected on average 18.94 points made on a 6 or 8, 13.33 on a 5 or 9, and 8.33 on a 4 or 10. Jan. 14, 2001"


Out of 100 points, how can 45.45 be 6/8, 40 be 5/9, and 33.33 be 4/10?? That adds up to over 100 points! Even if those were probabilities instead of hard numbers, they still add up to more than 100%. Am I not seeing something here?
miplet
miplet
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May 28th, 2010 at 8:18:42 AM permalink
Quote: IAchance5

Hi, I love wizard of odds website and it has a lot of great info, but I was reading the craps FAQ on probability and it states:

"On average, during the course of 100 points being established in craps: (1) How many of those would be 4/10, 5/9 or 6/8, (2) During the 100 how many times would each point (4/10, 5/9, 6/8) vs. a 7 being rolled. — Jon Moriarty from Danville, New Hampshire

Of those 100 points established, on average 45.45 would be on a 6 or 8, 40 would be on a 5 or 9, and 33.33 would be on a 4 or 10. You could expected on average 18.94 points made on a 6 or 8, 13.33 on a 5 or 9, and 8.33 on a 4 or 10. Jan. 14, 2001"


Out of 100 points, how can 45.45 be 6/8, 40 be 5/9, and 33.33 be 4/10?? That adds up to over 100 points! Even if those were probabilities instead of hard numbers, they still add up to more than 100%. Am I not seeing something here?


Even wizards make mistakes. total and winner 41.67 and 18.94 for 6/8, 33.33 and 13.33 for 5/9, 25 and 8.33 for 4/10
“Man Babes” #AxelFabulous
DJTeddyBear
DJTeddyBear
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May 28th, 2010 at 8:41:21 AM permalink
That question comes from the https://wizardofodds.com/ask-the-wizard/craps-probability/ page.

I was about to say that I think you found some typos.

Then I started to work the math:

24 out of 36 come out rolls are points, so only 24 rolls matter.

Out of those 24 rolls, 6 will be 4 or 10, 6/24 =.25
Out of those 24 rolls, 8 will be 5 or 9, 8/24 =.33
Out of those 24 rolls, 10 will be 6 or 8, 10/24=.42

Once a point is established, all rolls other than the point and 7 don't matter, so the odds of hitting the point vs 7 is calcuated by the combinations of the point, divided by those combinations plus the six combinations of 7.

Point of 4 or 10: 3/9=.33
Point of 5 or 9: 4/10=.40
Point of 6 or 8: 5/11=.45

You then multiply those two sets to find out the chance of a particular point pair hitting and then winning:
4 or 10: .25*.33=.0833
5 or 9 : .33*.40=.1333
6 or 8 : .42*.45=.1894

The Wiz's numbers are right. It's his description that could use a little tweaking.
I invented a few casino games. Info: http://www.DaveMillerGaming.com/ ————————————————————————————————————— Superstitions are silly, childish, irrational rituals, born out of fear of the unknown. But how much does it cost to knock on wood? 😁
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