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Everyone sits South in BBO Is there bias in the way that hands are dealt in BBO

#21 User is offline   Vampyr 

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Posted 2020-August-01, 10:38

 paulg, on 2020-August-01, 05:59, said:

It was first come, first served but traditionally certain places were left for particular pairs because they'd be upset if they had to sit elsewhere. It was, and is, an accommodating friendly club.

Now we toss for direction on most nights or draw for position in sim pairs.


It doesn’t sound that friendly or accommodating if there are people who throw a hissy fit if they don’t get to sit where you want.

 hrothgar, on 2020-August-01, 09:34, said:

I suspect that the proposed dynamic is that

Players who serve tables are more likely to be established pairs AND
Players who serve tables are more likely to sit N/S


In real bridge the management and/or director serves all the tables,
I know not with what weapons World War III will be fought, but World War IV will be fought with sticks and stones -- Albert Einstein
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#22 User is offline   hrothgar 

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Posted 2020-August-01, 12:23

 Vampyr, on 2020-August-01, 10:38, said:

In real bridge the management and/or director serves all the tables,


Online bridge is not the same as F2F bridge.

At the most basic level, the overwhelming majority of games don't have "management", nor are there directors.
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#23 User is online   smerriman 

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Posted 2020-August-01, 14:10

 pilowsky, on 2020-August-01, 06:17, said:

Incorrect. The number of IMPS is the only important thing. The scoreline is what matters; in the end, nothing else matters - that is what points schmoints means. That is why it's an interesting game.

Also, your use of the adverb 'completely' is ludicrously and ridiculously unscientific and will not be permitted. Two pairs of robots each alike in dignity play the same 6 sets of 12 boards.
In the end, NS achieves the same aggregate result as EW.
Therefore, there is no bias in the way that the hands are dealt. quod erat demonstrandum.

OK, you cannot seriously be anything other than trolling this forum now if you can't even follow basic logic. But I'll try once more, who knows why. Here are some very basic questions for you to answer.

If IMPs averaging to 0 proves the lack of bias, who do you think will get more IMPs if there is a bias? The side that gets dealt more HCP? What if the HCP are distributed evenly, but the hands are always Goulash-style? Why would Goulash not average to 0?

In particular, who do you think will get more IMPs if there is a bug in the algorithm that will result in South getting dealt 13 spads every hand?

N/S will make 7S. Every other N/S will make 7S. N/S will receive exactly 0 IMPs.

No matter *what* the dealing algorithm is, the average number of IMPs N/S will receive per hand is 0, because IMPs solely measure how N/S compare to all other N/S at other tables, no matter how bad/good the hand. That's the whole point of duplicate scoring.

Or take daylongs. There is clearly a bias there, since South is always given the best hand. Are you saying the human scores in a daylong should average more than 0 IMPs? Because last I checked, that's mathematically impossible.
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#24 User is offline   pilowsky 

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Posted 2020-August-01, 21:25

 hrothgar, on 2020-August-01, 06:10, said:

Listen shiite for brains, I know that you're a short timer, don't know anyone on the forums, and seems to have some need to go and swing your dick around, so here's a bit of background information

I have multiple graduate degrees in this stuff including two from MIT.
(I graduated from there with almost a 5.0 average)

The job that I held before this one was the product manager for MATLAB's statistics system.
The job that I currently hold is Principle Data Scientist at Akamai

As for your "contributions" to this thread.

The Nyquist–Shannon sampling theorem comes out of signal processing. It describes the relationship between the frequency of a signal and the sample rate. It doesn't get used to determine the sample size for observational studies. It doesn't get used for classical power calculations.

> The robots were given random hands to play and random
> results were collected. They are not double-dummy.
> There is only one dummy in this conversation.

I agree.
It is the person who doesn't know that GIB uses double dummy solvers to determine its line of play


I'm really delighted to discover that Akamai has decided to employ a data scientist with principles.

KS is not the best test. Better is the G-test for independence. I simplified it for the Forum so that a comparison could be made with Chi-squared. Neither are necessary because the result is bleeding obvious.
It does not matter what underlying software process GIB uses. What GIB does do is simulate.
You have been told this multiple times on the forum. Please listen. I only had to be told once but I am a fast learner. It may use the DD to simulate, but that does not mean that the 'simulation' is correct.
You are only 'correct' until your opponent makes their next move. This is true for all equilibrium games. It is true in life as well. Everything is 'obvious' when you know what happened.

Recently several people on the Forum complained that the deals were biased on BBO.
Think about what they mean. Did they mean that they did not they they did not get enough Aces? enough Kings enough spades? Wake up. What did they mean?
To help people you need to step into their shoes to answer their question. What people are saying is: When I play against other people of roughly equal ability and I am sitting EWN or South I seem to lose more often.
These people are NOT asking a mathematical question they are asking something else entirely. They are getting bad scores and they are blaming it on the cards that they are being dealt or the seat they are sitting in or the weather or the Jews or something else equally nonsensical. This is the reason Trump got elected. Because people thought they could solve all their problems by magic.


What I have done here is to demonstrate empirically - that there is no ghost in the machine. Pit four robots against each other and it does not matter where they are seated EW is just as likely to come out on top as NS.


Being competent in one area does not ensure competence in every area.
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#25 User is offline   pilowsky 

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Posted 2020-August-01, 21:41

 smerriman, on 2020-August-01, 14:10, said:

OK, you cannot seriously be anything other than trolling this forum now if you can't even follow basic logic. But I'll try once more, who knows why. Here are some very basic questions for you to answer.

If IMPs averaging to 0 proves the lack of bias, who do you think will get more IMPs if there is a bias? The side that gets dealt more HCP? What if the HCP are distributed evenly, but the hands are always Goulash-style? Why would Goulash not average to 0?

In particular, who do you think will get more IMPs if there is a bug in the algorithm that will result in South getting dealt 13 spads every hand?

N/S will make 7S. Every other N/S will make 7S. N/S will receive exactly 0 IMPs.

No matter *what* the dealing algorithm is, the average number of IMPs N/S will receive per hand is 0, because IMPs solely measure how N/S compare to all other N/S at other tables, no matter how bad/good the hand. That's the whole point of duplicate scoring.

Or take daylongs. There is clearly a bias there, since South is always given the best hand. Are you saying the human scores in a daylong should average more than 0 IMPs? Because last I checked, that's mathematically impossible.


Stephen, you throw the term 'troll' around but clearly do not know what it means. A 'troll' is a person whose sole motivation is to inflame and cause damage. What I am doing is stimulate conversation, education and assist people. Unlike many on this forum I never 'characterise', I am never rude, dismissive or abusive. When I provide explanations I do so within the limits of my knowledge base. I do not stroll outside of them.
When I want to learn something I ask questions.
Sometimes I ask questions that appear 'incompetent'. If I knew the answer, why would I ask the question? Only people that are trying to show off pose problems or ask questions when they already know the answer.

There is confusion about the usage of the word troll. The true troll is like an arsonist the have a psychopathology. They just want to see pain and suffering - that is how they get pleasure.
This is being misused in the media to refer to 'Russian troll farms'. These are not trolls. these are disinformation units of the FSB (formerly KGB) which reports to Putin (formerly head of the KGB).
Their actions are very purposeful. They want to destroy the government in the USA.

Obviously the strength in Daylongs is biased. What my 'little' experiment proves is that the hands dealt in the rest of BBO world are not hands re-used from daylongs. If they were then South would definitely get higher HCP counts.
This 'little' experiment should put peoples minds at ease.
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#26 User is online   smerriman 

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Posted 2020-August-01, 21:44

 pilowsky, on 2020-August-01, 21:25, said:

Recently several people on the Forum complained that the deals were biased on BBO.
Think about what they mean. Did they mean that they did not they they did not get enough Aces? enough Kings enough spades? Wake up. What did they mean?
To help people you need to step into their shoes to answer their question. What people are saying is: When I play against other people of roughly equal ability and I am sitting EWN or South I seem to lose more often.
These people are NOT asking a mathematical question they are asking something else entirely. They are getting bad scores and they are blaming it on the cards that they are being dealt or the seat they are sitting in or the weather or the Jews or something else equally nonsensical. This is the reason Trump got elected. Because people thought they could solve all their problems by magic.


There have been lots of examples of recent posts where people claim there is bias in the the *dealing algorithm*, with claims that one side gets dealt more HCP than the other, hands are more distributional than expected, suits don't break as expected, finesses always lose, and so on. None of these have anything to do with IMPs, since they affect all N/S at the other tables equally.

I can't think of a single example of a recent thread where someone is complaining anything resembling what are you suggesting. Do you have an example?
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#27 User is online   smerriman 

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Posted 2020-August-01, 21:52

 pilowsky, on 2020-August-01, 21:41, said:

What my 'little' experiment proves is that the hands dealt in the rest of BBO world are not hands re-used from daylongs. If they were then South would definitely get higher HCP counts.

Where in your results did you show that South did not get higher HCP counts? I cannot see any signs of this in any of your results. Only the irrelevant IMP scores.

Edit - in fact, don't bother replying. Had enough of feeding this troll.
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#28 User is offline   pilowsky 

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Posted 2020-August-01, 22:07

 smerriman, on 2020-August-01, 21:52, said:

Where in your results did you show that South did not get higher HCP counts? I cannot see any signs of this in any of your results. Only the irrelevant IMP scores.

Edit - in fact, don't bother replying. Had enough of feeding this troll.


Of course, some people are resistant to education, but that will not stop me from trying. Hope springs eternal.
Good luck partner.
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#29 User is offline   hrothgar 

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Posted 2020-August-01, 23:23

 pilowsky, on 2020-August-01, 21:25, said:

Being competent in one area does not ensure competence in every area.


Once again Fckwit, the only thing that you have done is spout a bunch of nonsense that you clearly don't understand

Lets deal with one of your most basic claims:

Quote

I have used at least double the sample size needed as per the Nyquist theorem.


"What's the Frequency, Kenneth?"

and why is the data that you are posting so clearly inconsistent with your hypothesis?

I think that your basic claim is correct.
BBO's Dealer isn't biased.

But your data doesn't show this, and it doesn't show this because you didn't take nearly enough samples.
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#30 User is offline   pilowsky 

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Posted 2020-August-01, 23:34

your spelling hasn't improved, neither has your knowledge of statistics. At least you are a man of principals.
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#31 User is offline   hrothgar 

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Posted 2020-August-02, 03:39

 pilowsky, on 2020-August-01, 23:34, said:

your spelling hasn't improved, neither has your knowledge of statistics. At least you are a man of principals.


Once again, you are refusing to engage with the basic comments that people are raising

Why? Because because you can't actually respond constructively to the points that I made.
The only thing that you can do is try to distract and run away.
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#32 User is offline   shyams 

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Posted 2020-August-02, 03:51

 hrothgar, on 2020-August-02, 03:39, said:

 pilowsky, on 2020-August-01, 23:34, said:

your spelling hasn't improved, neither has your knowledge of statistics. At least you are a man of principals.


Once again, you are refusing to engage with the basic comments that people are raising

Why? Because because you can't actually respond constructively to the points that I made.
The only thing that you can do is try to distract and run away.

So true.

hrothgar, something you will find funny (I hope). He criticises your spelling and then goes on to misspell principles :lol: :lol: :lol:
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#33 User is offline   pilowsky 

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Posted 2020-August-02, 04:02

Shyams, recruit your other brain cell into the conversation.
Here is how Richard attempted to impress us with his astonishing CV in an earlier post:

"The job that I held before this one was the product manager for MATLAB's statistics system
The job that I currently hold is Principle Data Scientist at Akamai"

I just thought it was a delightful choice of words for such a highly-strung man of principles - or perhaps Akamai looks after value systems and Richard really is in control of all of them WTF do I really care.
Maybe Akamai is where Trump should go to buy some Ethics. If Richard is the Data Scientist for principles I'm sure he could give him some really significant ones.
I'm reminded of Ryan O'Neal telling his daughter that he had scruples in Paper Moon. She replies "I don't know what they are but if you've got them you stole them from someone else".

smerriman has told me not to put in large blocks of text so if you want to find out about me you can use Mr Google.
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#34 User is offline   shyams 

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Posted 2020-August-02, 04:18

 pilowsky, on 2020-August-02, 04:02, said:

Shyams, recruit your other brain cell into the conversation.
Here is how Richard attempted to impress us with his astonishing CV in an earlier post:

"The job that I held before this one was the product manager for MATLAB's statistics system
The job that I currently hold is Principle Data Scientist at Akamai"

I just thought it was a delightful choice of words for such a highly-strung man of principles - or perhaps Akamai looks after value systems and Richard really is in control of all of them WTF do I really care.
Maybe Akamai is where Trump should go to buy some Ethics. If Richard is the Data Scientist for principles I'm sure he could give him some really significant ones.
I'm reminded of Ryan O'Neal telling his daughter that he had scruples in Paper Moon. She replies "I don't know what they are but if you've got them you stole them from someone else".

smerriman has told me not to put in large blocks of text so if you want to find out about me you can use Mr Google.


What conceit! You are an utter bore.
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#35 User is offline   AL78 

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Posted 2020-August-02, 04:27

 Vampyr, on 2020-August-01, 10:38, said:

It doesn’t sound that friendly or accommodating if there are people who throw a hissy fit if they don’t get to sit where you want.



That is what happened at my local (physical) bridge club years ago when the committee decided for consistency reasons, all evenings should have random seating, when at the time the Thursday evening people sat where they liked.
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#36 User is offline   AL78 

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Posted 2020-August-02, 04:48

 hrothgar, on 2020-August-01, 23:23, said:

Once again Fckwit, the only thing that you have done is spout a bunch of nonsense that you clearly don't understand

Lets deal with one of your most basic claims:



"What's the Frequency, Kenneth?"

and why is the data that you are posting so clearly inconsistent with your hypothesis?

I think that your basic claim is correct.
BBO's Dealer isn't biased.

But your data doesn't show this, and it doesn't show this because you didn't take nearly enough samples.


From my recollection there is a significance test that can be used to test whether a sample is likely to have come from a different distribution to some other distribution, usually setting the significance level to 5% or lower. The name escapes me at the moment.

The bridge hand HCP distribution is unusual compared to real life distributions in that we know exactly what it is, because there are only a finite number of bridge deals. The distribution is very close to normal, not actually normal because it is bounded by zero and 37. I would think it is close enough to normal that statistical methods could be used that rely on normality as an assumption.

If I were doing a bias test, I'd take the sample I'd got, note the number of deals in it, then randomly take the same number of deals from the full distribution of deals a large number of times (say one million) and compute the HCP for each rendom sample. The HCP of the real sample can be compared to where it falls on this distribution of one million random samples, this distribution will be approximately normal by the central limit theorem. If, by this distribution, the probability of obtaining the HCP of the real sample is <= 5%, the sample is likely to be biased. It doesn't guarentee bias since if the p-value of the sample is 5%, it could still be unbiased and you happen to have got the one in twenty unbiased samples that lie in the 5% tail.
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#37 User is offline   pilowsky 

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Posted 2020-August-02, 04:55

It's ridiculous - otherwise apparently normal 70+-year-old men fighting over seats on a Wednesday night. My friends regular Wednesday partner, Perry used to race in early to the Club to grab the North seat on Table 14 so that Chaim couldn't get it.
C. Northcote Parkinson and FM Cornford wrote about in the civil service and academia respectively.
(names changed for no particular reason)
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#38 User is offline   hrothgar 

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Posted 2020-August-02, 05:08

 AL78, on 2020-August-02, 04:48, said:

From my recollection there is a significance test that can be used to test whether a sample is likely to have come from a different distribution to some other distribution, usually setting the significance level to 5% or lower. The name escapes me at the moment.


There are a number of them.

The one that I used earlier in this thread is the Kolmogorov–Smirnov test
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#39 User is offline   pilowsky 

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Posted 2020-August-02, 06:55

The correct test is the G-test for independence, not the KS.
But you have to know about statistics to know that.
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#40 User is offline   AL78 

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Posted 2020-August-02, 07:02

 pilowsky, on 2020-August-02, 06:55, said:

The correct test is the G-test for independence, not the KS.
But you have to know about statistics to know that.


I've use KS to test for likely deviation of a distribution from normality, I've never heard of the G test until now.
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