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janeg
Regina Canada
Joined: 04 Oct 2004
Posts: 5228
Location: Somewhere down the crazy river
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 Posted: Mon Aug 13, 2007 10:34 pm Post subject: Bayes Theorem |
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First came across this in The Mathematics of Poker by Bill Chen and Jerrod Ankenman. Can't say I understand it fully but found a site that helps make it a little clearer: An Intuitive Explanation of Bayesian Reasoning. Just in case others are scratching their heads over it  |
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darvon
BCS Neutral
Joined: 28 Feb 2004
Posts: 5478
Location: Detroit
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| Posted: Mon Aug 13, 2007 11:54 pm Post subject: |
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I got the original problem correct and lost interest.
Looks pretty obvious to moi. |
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cybrarian
Retired Moderator
Joined: 05 Dec 2003
Posts: 11392
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| Posted: Tue Aug 14, 2007 2:41 am Post subject: |
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| I think it's non-obvious to a lot of people, who might find that link useful. |
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AlamedaMike
2K Club
Joined: 29 Jun 2005
Posts: 2042
Location: Alameda, CA
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| Posted: Wed Oct 10, 2007 1:36 pm Post subject: Re: Bayes Theorem |
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| janeg wrote: | | First came across this in The Mathematics of Poker by Bill Chen and Jerrod Ankenman. Can't say I understand it fully but found a site that helps make it a little clearer: An Intuitive Explanation of Bayesian Reasoning. Just in case others are scratching their heads over it |
Did you like the book and do your recommend it? Thanks for the link.
It is also in one of Sklansky's books. I'm not sure which one at the moment.
Edit - Getting the best of it - my mind glazed over. |
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nsidestrate
Suited's Love Monkey
Joined: 26 May 2004
Posts: 22652
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| Posted: Wed Oct 10, 2007 2:07 pm Post subject: |
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| darvon wrote: | I got the original problem correct and lost interest.
Looks pretty obvious to moi. |
They get harder. This is a pretty good guide to Baysean logic. |
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AlamedaMike
2K Club
Joined: 29 Jun 2005
Posts: 2042
Location: Alameda, CA
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| Posted: Wed Oct 10, 2007 5:33 pm Post subject: |
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| nsidestrate wrote: | | darvon wrote: | I got the original problem correct and lost interest.
Looks pretty obvious to moi. |
They get harder. This is a pretty good guide to Baysean logic. |
Then darvon is pretty smart if it is obvious.
My sainted wife once said in such an innocent voice - 'its simple once you know how' - it was after I had explained the solution to a complex computer problem to her and she saw the light. None of her co-workers could understand it.
I understand the Bayes' theorem most of the time and kind of: Look at this definition and see how clear it is.
getting the best of it Sklansky gave a very simple example. There is a 10 horse race and there are 3 fillies, A, B and C. Each has a probability of winning 5, 10 and 15 % respectivily. You left before the race won and after the race heard that a filly won, what was the probability that horse A won?
Or you place a bet with your friend that filly A will win if a filly wins. What are the odds to make a good bet? |
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janeg
Regina Canada
Joined: 04 Oct 2004
Posts: 5228
Location: Somewhere down the crazy river
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| Posted: Wed Oct 10, 2007 9:45 pm Post subject: Re: Bayes Theorem |
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| AlamedaMike wrote: | | janeg wrote: | | First came across this in The Mathematics of Poker by Bill Chen and Jerrod Ankenman. Can't say I understand it fully but found a site that helps make it a little clearer: An Intuitive Explanation of Bayesian Reasoning. Just in case others are scratching their heads over it |
Did you like the book and do your recommend it? Thanks for the link.
It is also in one of Sklansky's books. I'm not sure which one at the moment.
Edit - Getting the best of it - my mind glazed over. |
Hi Alameda...I'm not sure whether I like it or not, should recommend it, or not. I've done 1 1/2 reads so far and can't decide if it's worth the effort or not. The only thing I'm sure of is that a lot of the math is over my head  |
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AlamedaMike
2K Club
Joined: 29 Jun 2005
Posts: 2042
Location: Alameda, CA
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| Posted: Thu Oct 11, 2007 11:32 am Post subject: |
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| Thanks Jan - I have enought books to study right now anyway and I am not sure that my 60+ brain wants to deal with more math. |
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Bugsbunny
Wascally
Joined: 07 Apr 2004
Posts: 7715
Location: Drinking Carrot juice
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| Posted: Fri Oct 12, 2007 11:04 am Post subject: |
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| AlamedaMike wrote: | | nsidestrate wrote: | | darvon wrote: | I got the original problem correct and lost interest.
Looks pretty obvious to moi. |
They get harder. This is a pretty good guide to Baysean logic. |
Then darvon is pretty smart if it is obvious.
My sainted wife once said in such an innocent voice - 'its simple once you know how' - it was after I had explained the solution to a complex computer problem to her and she saw the light. None of her co-workers could understand it.
I understand the Bayes' theorem most of the time and kind of: Look at this definition and see how clear it is.
getting the best of it Sklansky gave a very simple example. There is a 10 horse race and there are 3 fillies, A, B and C. Each has a probability of winning 5, 10 and 15 % respectivily. You left before the race won and after the race heard that a filly won, what was the probability that horse A won?
Or you place a bet with your friend that filly A will win if a filly wins. What are the odds to make a good bet? |
Still pretty simple
Probability that horse A won = 16.7%
Probability that horse B won = 33.3%
Probability that horse C won = 50%
True odds on Horse A for the bet with the friend are 5 to 1
True odds on Horse B for the bet with the friend are 2 to 1
True odds on Horse C for the bet with the friend are 1 to 1
(All of those answers assume that A, B, and C are the ONLY fillies in the race - something which isn't 100% clear from the way the question is phrased. Which means that the truly correct answer is "Unable to determine with the information given"). |
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AlamedaMike
2K Club
Joined: 29 Jun 2005
Posts: 2042
Location: Alameda, CA
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| Posted: Wed Oct 17, 2007 10:31 am Post subject: |
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| A fillie did win and you are right as always. The probability that horse A won given that A, B or C won is 5-1. |
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