--- In vpFREE@yahoogroups.com, "Harry Porter" <harry.porter@...>
wrote:
dunbar_dra wrote:
>
> Harry, there are a couple of things in your post that are not
clear
> to me. You wrote:
>
> "The truth is that in general terms it isn't until you've
witnessed
> 20 cycles of an event that you have an inkling as to whether
you're
> truly experiencing anomalous results. By "anomalous", I'm
referring
> to results that deviate no more than 10% from expectation. And
even
> then, you only have 68% confidence that your results truly do
> represent an aberration. if you want 95% confidence, you need to
play
> through 60 cycles."
>
> I'm guessing that the cycles you give are for a deviation from
> expectation of exactly 10% instead of "no more than 10%".
Otherwise
> there could not be a single number of cycles that would fit the
> bill.
Well, that statement is certainly cause for pause, coming from
you.
However, I stand by my wording.
Well, let me qualify that ... I should have written "20%",
not "10%".
(I've been very intently working on a project this week ... the
4am
posting reflected an obsessive stirring from my sleep after only a
couple of hours in bed. Allow me that one lapse, ok? 
In any case, what I suggest is that having played 20 cycles of
play,
68% of the time the number of time the related event will occur
within
the bounds of +/- 20% of 20, i.e. between 16 and 24 times. (This
can
be confirmed with a binomial distribution.)
The probability of a deviation of exactly +/- 20% (i.e., the event
being observed either 16 or 24 times) is 12%.
I'm still having a problem with your original wording, Harry. You
wrote:
"The truth is that in general terms it isn't until you've witnessed
20 cycles of an event that you have an inkling as to whether you're
truly experiencing anomalous results. By "anomalous", I'm referring
to results that deviate no more than [20%] from expectation. And even
then, you only have 68% confidence that your results truly do
represent an aberration."
I now think you meant "results that deviate more than 20%" instead
of "...no more than 20%". If the "anomalous" result differed by a
mere 1%, then you would need a lot more than 20 cycles to get 68%
confidence. (In fact, there isn't such a thing as a 1% anomaly in
RF frequency until you get to 100 cycles!)
I'm 100% sure you understand the concept, but I just want to set the
wording straight. (I was so sure you understood it, that I accepted
your 10% figure without checking it. Just like I'm still not
checking your 20% figure!)
> Later, you wrote:
>
> "The truth is even if you've played through 10-15 cycles in that
time
> (400,000 to 600,000 hands) you haven't even come close to a
basis for
> a reasonable suspicion. If you've merely played through 6 cycles
> royalless, you haven't a ghost of a clue. But you're unlikely to
> convince some casual players of that. (You might gather that this
> isn't an entirely "off the top of my head" example ;)"
>
> You must be talking about the 10% deviation still, right?
Because
> if you are talking about 400,000 to 600,000 hands with no royal,
I'd
> have to disagree with you!
Absolutely (well ... make that 20% <sheepish grin>). This is a
continuation of a scenario in which the 20% deviation and 68%
confidence level are the selected thresholds for suspicion (which,
as
I separately discuss, are chosen in direct relation to one's
tolerance
for a deviation before suspicion).
> Even 6 cycles with no royal would be grounds for "reasonable
> suspicion" under the right circumstances. An example of wrong
> circumstances would be if the drought was counted from
immediately
> after an RF. (ie, it was really 1 RF in 240,001 hands instead
of no
> RF's in 240,000 hands). An example of what might be right
> circumstances would be if I walked into an Indian casino and
played
> my first 240,000 hands of JOB without an RF. An example of what
> (for me) would definitely be right circumstances would be if I
> walked into an Indian casino and said (to myself), "I am going
to
> play 240,000 hands of JOB, and if I don't hit at least 1 RF in
that
> stretch, I am going to quit." With a "test" structured like
that,
> there's only 1 chance in 380 that I would get no RF's in 240,000
> hands by chance alone. I'm willing to live with the 0.26%
chance
> that my suspicions are ill-founded! ;>)
Agreed, with the caveat that I raise in another post (and first
admirably noted by Tom Robertson). The version of this test that
most
players are likely to employ is, "If I don't hit at least 1 RF in a
stretch of any 240,000 hands, I'm going to quit". And, most often,
such a test is employed retroactively, after they become aware that
they've suffered a dry stretch.
That's a very good way to put it, and yes, I agree completely. Most
people do put too much weight on retroactively observed events with
fluid start and stop times.
You haven't suggested the test in that manner and I know that I
don't
need to tell you that such a "test" isn't an adequate measure of
gaffeness. However, I have little doubt that the great majority of
players who cry "gaffe" have done exactly that. In such a case,
it's
merely a flag that it may be reasonable to begin the clean test you
suggest starting with the next play.
Agreed. Also, as I know both you and NOTI understand very
well, there's nothing magic about 6 cycles. If someone is willing
to be wrong 2% of the time, he/she can use a 4-cycle drought as the
bailout threshold from a new game/casino. As long as they tell
themselves that ahead of time! ;>)
--Dunbar