vpFREE2 Forums

Determining if a vp game is gaffed

#1

I'll take an initial stab at this.? There are several factors to consider.? The most important one is deciding what you are looking for before you start.? The second most important factor is accurate record keeping.? If you play for a couple of hours, keeping track of dealt trips can be tough if you don't write things down.

Here are the steps I would take.? Actually, if I thought a machine was non random I wouldn't play it.? For the sake of discussion, here's how I would approach the problem:

1) State?the suspect characteristic of the machine, i.e 3 Aces never fill into Quads.

2)? Figure out the frequency of a success.? In this case, you are dealt 3 aces about once is 650 hands.? You fill in once in 23.5 hands so on average, you will convert 3 aces into quads 1 in 2470 hands ( rounded).

3) Figure out a decent sample size.? This is easier said than done.? Nyquist Theory says a minimum of 2 times the frequency.? I have heard Dan Paymar mention he likes 10 times the frequency.? The appropriate sample size is also determined by how badly gaffed the machine is.? If it never gives quad aces from trips, that is a much easier event to detect than saying it gives them one out of 50 times instead of 1 out of 23.5.? I'll use 10 times the success frequency as a starting point.

4) Collect accurate data.? Once again, easier said than done, especially if keeping track in your head.

5) Apply the appropriate statistics to the data.? The binomial distibution is useful but you also need some other information, like the?Z Test.?

The Z-test is a statistical test used in inference which determines if the difference between a sample mean and the population mean is large enough to be statistically significant.

This will tell you how likely it is that your result is a 'valid' result.

Wow, this is a pretty good question.? I will work on it some more and sent the file to VP Fae for discussion.

Why is it that working stats problems for video poker is more interesting than doing them for work?

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#2

greeklandjohnny wrote...

The Z-test is a statistical test used in inference which determines if the difference between a sample mean and the population mean is large enough to be statistically significant.

This will tell you how likely it is that your result is a 'valid' result.

Wow, this is a pretty good question.? I will work on it some more and sent the file to VP Fae for discussion.

Why is it that working stats problems for video poker is more interesting than doing them for work?

The vpadministrator posted in the vpFREE file section the file
"Deal_Redeal.xls", 100 hands for the deal and the redeal that I did on
my IGT machine. This is certainly a very small sample but I suspect
that this is the type of data needed in order to determine if a machine
is gaffed. How many hands are needed for a statistical answer?

Dennis
vp-connoisseur

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#3

3) Figure out a decent sample size.? This is easier said than done.?
Nyquist Theory says a minimum of 2 times the frequency.? I have heard Dan
Paymar mention he likes 10 times the frequency.?

Nyquist Sampling Rate Theorem only applies to periodic functions. Card games
are more akin to Poisson functions, so Nyquist sampling wouldn't apply

The appropriate sample size
is also determined by how badly gaffed the machine is.? If it never gives
quad aces from trips, that is a much easier event to detect than saying it
gives them one out of 50 times instead of 1 out of 23.5.? I'll use 10 times
the success frequency as a starting point.

So, by your theory, you would need 235 trip aces, or on average about 580,500
hands. At 700 hands/hour, you are talking about 829 hours, or almost 21 weeks of
full time play.

In other words, it's nearly impossible to tell.

Edmund

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On Nov 8, 2007 9:20 PM, <greeklandjohnny@aol.com> wrote:

#4

Your initial stab is the sort of input that I was hoping for.

I'll work with you to refine the procedures and we'll
link them to the FAQ question.

Additional stabs from anyone else will be appreciated.

vpFae
vpFREE DataBase Coordinator
vpFae@Cox.net

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On 8 Nov 2007 at 22:20, greeklandjohnny@aol.com wrote:

I'll take an initial stab at this ...

#5

So many times I have been told by someone who is not hitting that the
machines had been gaffed. I politely ask how they know that. They
invariably will tell me they know a technician who "used" to work
there and they told them so.

I then politely ask them "Then why are you playing the machine?"

I usually get a fillabuster of words that have no sense to them and/or
they just shut up and tell me they "just know"