Sometimes a little knowledge is a dangerous thing.
Just because you stick numbers into a statistical package and it
generates reams of output doesn't mean you have understanding of the
situation, or that your results are meaningful. Do you have any idea
how to apply the Central Limit Theorem CLT, or even what the central
limit theorem is? One important characteristic that effects the
ability to apply CLT is how close the underlying distribution is to
the Normal distribution. The answer in our case is not very close.
The normal distribution is a symetric distribution.
In indidvidual trials of video poker hands the resutls are extremely
skewed. On one hand (5 coin bet) you could win 4000 coins, the most
you could lose is 5 coins. This would greatly increase the number of
trials you would need before CLT can be applied and you could
mindlessly enter the numbers into your stat package.
Any simple thought experiment would point out how silly your
hypotheseis testing results are.
As any stat prof. will tell you these days, the real danger in
reading statistical results today is having confidence in the person
running the software. Anyone can stick numbers into a stat package,
having a ral understanding of statistics is another thing. I'm glad
you know how to run your stat package and paste the results in eMail
messages, the next step is to learn statistical theory.
Trying to draw meaningful inferences from a sample of 2000 where the
period is 40,000 is silly.
--- In vpFREE@yahoogroups.com, "nightoftheiguana2000"
<nightoftheiguana2000@y...> wrote:
just to summarize the results from the lotspiech calculator:
fpdw, stake=$340, retire=$95, 2000 hands ($1.25/hand)
<-$340 1.8%
-$340to-$295 1.6%
-$295to-$250 4.2%
-$250to-$205 7.0%
-$205to-$160 9.4%
-$160to-$115 10%
-$115to-$70 9.6%
-$70to-$25 7.4%
-$25to+$20 4.8%
+$20to+$65 2.3%
+$65to+$95 0.40%
>+$95 40%
so, if you get less than -$340 in actual play, you have 1.8%
confidence that the machine is honest, if you get -$125 in actual
play, you have 10% confidence that the machine is honest, if you get
over +$95 you have 40% confidence
if you are trying to prove that the machine is honest with greater
confidence, you will have to play more hands
however, if you are trying to prove that the machine is fixed, and
you
get less than -$340, you have 98.2% confidence that it is fixed (or
you are playing incorrectly)
best option at that point would be to report your findings to the
local regulation board and here (make note of machine number) and
find
a different machine
if you insist, you can continue playing and evaluating, the worse
the
results and the more hands the greater your confidence will be
that you've found a loser
--- In vpFREE@yahoogroups.com, "nightoftheiguana2000"
<nightoftheiguana2000@y...> wrote:
>
> hmm, yeah, i see the problem
> ok, i'm still gonna hold to this though:
> let's say you have a sample of 2000 hands, and your results are
-$339,
> and we have figured out that the probability of this occuring
with a
> legit fpdw is 1.8%
> so, based on this sample size, we have 1.8% confidence that it
comes
> from a legit fpdw machine and 98.2% confidence that the machine is
not
> a legit fpdw?
> if our results were -$300, it would shift to something like
5%/95%?
> since our sample size is too small for deuces and royals we are
> expecting a mean of -5% (2000x$1.25x-.05=-$125)
> if our sample came in at -$125, would we have 100% confidence?
> this is where harry takes over
> good luck harry
> (i still think if you get -$339 it's 98.2% likely you've got a bum
> machine or are suffering some sort of pilot error)
>
> --- In vpFREE@yahoogroups.com, "Harry Porter" <harry.porter@v...>
> wrote:
> >
> > nightoftheiguana2000 wrote:
> >
> > > well, if one session falls below expected range, in this case
> $339,
> > > you have 1.8% confidence that the machine is not biased
> > >
> > > let's assume you play another 2000 hand session
> > > if you fell below $339 again, you would have (1.8%)^2 = .03%
> > > confidence that the machine is not biased (99.97% confidence
that
> it
> > > is)
> > >
> > > it's just probabilities
> > > not below range= 98.2% confidence in machine, 1.8% confidence
> > > against machine below range= 1.8% confidence in machine,
98.2%
> > > confidence against
> > >
> > > probability of machine not being below range
twice: .982^2=96.4%
> > > probability of machine being below range twice: .018^2=0.03%
> > > probability of one session above, one session below:
> > > 100-96.4-.03=3.57%
> >
> >
> > Thanks for the info, iggy ... much appreciated.
> >
> > I've quoted the text for which I'm being just a little slow on
the
> > uptake. Humor me, ok 
> >
> > If I'm reading this right, you seem to suggest that on just one
> trial
> > of 2000 hands you'll have 98.2% confidence in your assessment of
the
> > fairness of the machine.
> >
> > Now, I suspect I'm interpreting something incorrectly here. I
read
> > this to say that if the result of your session was a loss of
$330,
> > then the interpretation that the machine is fair is made with
98.2%
> > confidence. On the other hand, if the loss were $350, you have
> 98.2%
> > confidence that the machine is negatively biased.
> >
> > You see my problem here. That seems to be a very small
difference
> in
> > loss to sway the call that much. This was the driver behind my
> > assumption that it would take multiple 2000 hand trials to
arrive
···
as
> > an assessment with a large degree of confidence.
> >
> > Keep your hands on my shoulders, iggy, and steer me in the right
> > direction 
> >
> > - Harry