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Bob Dancer's LV Advisor Column - 31 JAN 2012

#1

Bob Dancer's LV Advisor Column - 31 JAN 2012

"Drawing Conclusions"

http://www.lasvegasadvisor.com/bob_dancer/2012/0131.cfm

<a href="http://www.lasvegasadvisor.com/bob_dancer/2012/0131.cfm">
http://www.lasvegasadvisor.com/bob_dancer/2012/0131.cfm</a>

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#2

I liked this article a lot, of course it's the kind of thing I write about all the time. I'd like to add this to what Bob said.

Even if you played the same machines an identical number of times two years running, imagine how unlikely it would be for your results to be identical as well. With randomness added the chances of identical results are so small as to be nearly impossible.

Now consider that with two different results in front of you, one has to be smaller, and the other has to be larger. That's just how it works when you compare two numbers.

So what solid conclusion can one make from comparing two results of a random process? Sadly, not a darned thing.

It would be like flipping two coins and trying to infer from the results which one had more heads on it. Look at the coins, make sure they have both heads and a tails for sides, but for goodness sake don't flip them and record the results to learn anything more.

~FK

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--- In vpFREE@yahoogroups.com, "vpFREE Administrator" <vpfreeadmin@...> wrote:

Bob Dancer's LV Advisor Column - 31 JAN 2012

"Drawing Conclusions"

http://www.lasvegasadvisor.com/bob_dancer/2012/0131.cfm

<a href="http://www.lasvegasadvisor.com/bob_dancer/2012/0131.cfm">
http://www.lasvegasadvisor.com/bob_dancer/2012/0131.cfm</a>

*************************************************
This link is posted for informational purposes
and doesn't constitute an endorsement or approval
of the linked article's content by vpFREE. Any
discussion of the article must be done in
accordance with vpFREE's rules and policies.
*************************************************

#3

This is just a minor point, but you could flip a coin (many times, of course) to determine if it was exactly balanced, and people have done just this, and it turns out most coins are not balanced. And (hopefully) Nevada Gaming Regulators do the equivalent when they test machines for randomness. Or do they just outsource the job to China?

http://stackoverflow.com/questions/56411/how-to-test-randomness-case-in-point-shuffling

The wikipedia article:
http://en.wikipedia.org/wiki/Coin_flipping
says most people coin flip with biases in the range of ".495 or .503".

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--- In vpFREE@yahoogroups.com, "Frank" <frank@...> wrote:

It would be like flipping two coins and trying to infer from the results which one had more heads on it. Look at the coins, make sure they have both heads and a tails for sides, but for goodness sake don't flip them and record the results to learn anything more.

#4

"How We Learned to Cheat at Online Poker: A Study in Software Security":

http://itmanagement.earthweb.com/entdev/article.php/616221

#5

On a related note, here is the Wizard's description of how he took some random slot results (212 spins) and figured out the game with them:
http://wizardofodds.com/games/slots/jackpot-party/

You can apply the same concept to video poker, there are 52 possible first cards, within 52 to 300 spins or so you should see all of them in that position at least once. The second spot has 51 cards, and so on. Each spot is supposed to be independent, with the one exception that no card should repeat, the deck is not infinite but is depleted by each draw. As a simple example, here are my one card draws from a deck of the five broadway cards:

KQKJQKQJAAKJT

13 draws: 2A, 4K, 3Q, 3J, 1T

···

--- In vpFREE@yahoogroups.com, "nightoftheiguana2000" <nightoftheiguana2000@...> wrote:

This is just a minor point, but you could flip a coin (many times, of course) to determine if it was exactly balanced, and people have done just this, and it turns out most coins are not balanced. And (hopefully) Nevada Gaming Regulators do the equivalent when they test machines for randomness. Or do they just outsource the job to China?

http://stackoverflow.com/questions/56411/how-to-test-randomness-case-in-point-shuffling

The wikipedia article:
http://en.wikipedia.org/wiki/Coin_flipping
says most people coin flip with biases in the range of ".495 or .503".

--- In vpFREE@yahoogroups.com, "Frank" <frank@> wrote:
> It would be like flipping two coins and trying to infer from the results which one had more heads on it. Look at the coins, make sure they have both heads and a tails for sides, but for goodness sake don't flip them and record the results to learn anything more.

#6

How does he know that each stop has the same probability of occurring?
It doesn't on machines with physical reels. I've never heard of a
machine with different numbers of stops on different reels, also.

nightoftheiguana wrote:

···

On a related note, here is the Wizard's description of how he took some random slot results (212 spins) and figured out the game with them:
http://wizardofodds.com/games/slots/jackpot-party/

You can apply the same concept to video poker, there are 52 possible first cards, within 52 to 300 spins or so you should see all of them in that position at least once. The second spot has 51 cards, and so on. Each spot is supposed to be independent, with the one exception that no card should repeat, the deck is not infinite but is depleted by each draw. As a simple example, here are my one card draws from a deck of the five broadway cards:

KQKJQKQJAAKJT

13 draws: 2A, 4K, 3Q, 3J, 1T

--- In vpFREE@yahoogroups.com, "nightoftheiguana2000" <nightoftheiguana2000@...> wrote:

This is just a minor point, but you could flip a coin (many times, of course) to determine if it was exactly balanced, and people have done just this, and it turns out most coins are not balanced. And (hopefully) Nevada Gaming Regulators do the equivalent when they test machines for randomness. Or do they just outsource the job to China?

http://stackoverflow.com/questions/56411/how-to-test-randomness-case-in-point-shuffling

The wikipedia article:
http://en.wikipedia.org/wiki/Coin_flipping
says most people coin flip with biases in the range of ".495 or .503".

--- In vpFREE@yahoogroups.com, "Frank" <frank@> wrote:
> It would be like flipping two coins and trying to infer from the results which one had more heads on it. Look at the coins, make sure they have both heads and a tails for sides, but for goodness sake don't flip them and record the results to learn anything more.

#7

nightoftheiguana2000 wrote:

On a related note, here is the Wizard's description of how he took some random slot results (212 spins) and figured out the game with them:
http://wizardofodds.com/games/slots/jackpot-party/

You can apply the same concept to video poker

Well, within some constraints. The key constraint is that Michael presumed for the slot game that the symbol distribution was random. Piece of cake, once you make that presumption.

When you start questioning the randomness (the initial subject you raised in this thread), evaluating expected return becomes much more complex. (For example, just because symbols occur on each reel with an observed frequency doesn't mean that the reels operate independently of each other).

Ditto, when it comes to vp evaluation when fairness comes into question.

#8

Good questions for the Wizard.

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--- In vpFREE@yahoogroups.com, Tom Robertson <007@...> wrote:

How does he know that each stop has the same probability of occurring?
It doesn't on machines with physical reels. I've never heard of a
machine with different numbers of stops on different reels, also.

nightoftheiguana wrote:

>On a related note, here is the Wizard's description of how he took some random slot results (212 spins) and figured out the game with them:
>http://wizardofodds.com/games/slots/jackpot-party/
>
>You can apply the same concept to video poker, there are 52 possible first cards, within 52 to 300 spins or so you should see all of them in that position at least once. The second spot has 51 cards, and so on. Each spot is supposed to be independent, with the one exception that no card should repeat, the deck is not infinite but is depleted by each draw. As a simple example, here are my one card draws from a deck of the five broadway cards:
>
>KQKJQKQJAAKJT
>
>13 draws: 2A, 4K, 3Q, 3J, 1T
>
>
>
>--- In vpFREE@yahoogroups.com, "nightoftheiguana2000" <nightoftheiguana2000@> wrote:
>>
>> This is just a minor point, but you could flip a coin (many times, of course) to determine if it was exactly balanced, and people have done just this, and it turns out most coins are not balanced. And (hopefully) Nevada Gaming Regulators do the equivalent when they test machines for randomness. Or do they just outsource the job to China?
>>
>> http://stackoverflow.com/questions/56411/how-to-test-randomness-case-in-point-shuffling
>>
>> The wikipedia article:
>> http://en.wikipedia.org/wiki/Coin_flipping
>> says most people coin flip with biases in the range of ".495 or .503".
>>
>>
>> --- In vpFREE@yahoogroups.com, "Frank" <frank@> wrote:
>> > It would be like flipping two coins and trying to infer from the results which one had more heads on it. Look at the coins, make sure they have both heads and a tails for sides, but for goodness sake don't flip them and record the results to learn anything more.
>>
>

#9

I agree, but as a first pass assuming the symbols are equally weighted and there is no correlation between reels seems like a reasonable assumption. It should be true in video poker and I think it is in a fair number of other slots, like jackpot party. To check for unequal symbol weighting and correlation between reels would require a larger sample set, but we're talking thousands or tens of thousands, not millions. In video poker the reels have 52 symbols but repeats are excluded (that would be one correlation that should never happen, if it does time to snap a pic and call gaming) so the possible correlations between any two reels are 52x51-2652. Here's an experiment: make up a deck of 4 Aces, 1 King and 1 Queen, then forget what the composition is. Start drawing one card and then reshuffle and repeat, recording your results. How many samples do you need before you begin to think there are multiple aces in the deck? How many samples do you need to begin to make a reasonable guess at how many extra aces are in the deck?

AAAKQAAKAAAQA...

9:2:2

···

--- In vpFREE@yahoogroups.com, "vp_wiz" <harry.porter@...> wrote:

nightoftheiguana2000 wrote:
>
> On a related note, here is the Wizard's description of how he took some random slot results (212 spins) and figured out the game with them:
> http://wizardofodds.com/games/slots/jackpot-party/
>
> You can apply the same concept to video poker

Well, within some constraints. The key constraint is that Michael presumed for the slot game that the symbol distribution was random. Piece of cake, once you make that presumption.

When you start questioning the randomness (the initial subject you raised in this thread), evaluating expected return becomes much more complex. (For example, just because symbols occur on each reel with an observed frequency doesn't mean that the reels operate independently of each other).

Ditto, when it comes to vp evaluation when fairness comes into question.