--- In vpFREE@yahoogroups.com, "Harry Porter" <harry.porter@...>
wrote:
> A few questions:
>
> Both of these will give me a graphical representation of the
outcomes
> of a given trip stake,using a given number of hands played during
the
> trip (I assume either you make the number of hands or bust
trying
> during each trip stake), and of course the game being played.
Is
> that correct?
On the money.
> Also, here I go again, but it seems to me that for rather small
> numbers of hands (say 2000, I pick 2000 because that is a good
number
> for me for a given daily trip), that the outcome distribution
would
> be skewed toward the high end. So my question is when does it
> supposedly become normal as some on this forum seem to state?
This
> distribution shape keeps getting kicked around and has never been
> clear to me when it becomes normal, if ever. I would think for
small
> quantities (again say 2000 hands) that it would never become
normal.
> Jazbo seems to support that it does not become normal.
>
> Like I said, I have always had a problem with this, but (maybe it
was
> a poor explanation on the part of the posters) I was led to
believe
> that the outcome distribution would become normal as stated on
vpFREE
> by more than one poster on more than one occasion.
>
> Somebody give me a good explanation please, when and where can
you
> assume normality? Or never?
As you observe (measured as "skewness"), in the short run we expect
far more losing sessions than winning sessions -- but the fewer
winning sessions will, at times, be large enough to balance things
out
to where the game EV is preserved.
As you extend the number of hands played, cumulative results begin
to
smooth out around the game EV; i.e. they start to distribute
themselves more equally around the mean. Once you look at play of
anywhere from 1MM to 10MM hands (the more volatile the game the more
hands needed), results become rather smoothly distributed around the
mean -- in loose terms, the point at which this is achieved is
deemed
the "long term" of play; i.e. we reasonably expect that our
cumulative
long term results will closely approximate game ER (in percentage
terms).
However, even at this extreme point, play results do not meet the
criteria that define a "normal" distribution; they merely
approximate
it. This may seem a bit paradoxical for we certainly expect that vp
probabilities overall adhere to a natural (aka "normal")
distribution
-- there's nothing that distinguishes them in nature from simply
flipping coins.
But, what's at work here is that vp results don't measure a single
hit-or-miss outcome, but rather the aggregation of payoffs from a
discrete set of hands (Pair, 2 Pair ... RF). If you look at the
distribution of return derived from hitting pairs alone it quickly
takes on a normal distribution. The same is true for every other
hand.
If each hand paid the same and occurred with the same frequency,
then
the aggregate distribution of results would also take on a normal
distribution in short order. However, the disparate frequencies and
payouts cause each hand to unevenly contribute to the overall
results
distribution ... and the hands that are least frequent and highest
paying are the ones that account for the bulk of a game's variance
statistic for, in addition to the high payout, they take the longest
for results to even out over the course of play.
Consequently, in the short run, when you aggregate the payout of
various hands you end up with a distribution that's misshapen --
where
a higher number of outcomes fall short of the mean and the results
to
the right are "long tailed". It's only after the least frequently
occurring hands take on a normal distribution that the overall
distribution starts approximating "normality" itself.
A general rule of thumb is that for a game where there's only a
single
low-frequency high-payout hand (e.g. Jacks vis-a-vis the RF), the
long
term is achieved after 20-30 cycles of the hand. Where there are
several such hands (e.g. DDB, w/ RF & qA w/kicker), a greater number
of cycles are required.
- Harry
Do Jazbo's curves agree with the above explanation? I may not have
asked the question properly, so I will try again,
Asuming I always play 1000 , 25c hands of NSUD (yes sometimes will
bust, but for now let that slide) For each of these sessions I take
$200 dollars with me and compute my win or loss as how much more than
$200 I take home that day, or how much less than $200 I take home
that day.
Then I make a distribution of my win, or loss for evey session/days
of 1000 hands. I would think that disrtibution would be centered
around a 0.3% of $1250 loss ($3.75 assuming perfect play) and skewed
toward the large win side and probably look like the curves that
Jazbo published. (use http://www.jazbo.com/ then vp
probabilities) It would further seem to me that the distribution
never would approximate the normal curve no matter if I did this 1000
hand session/trip for infinity.
Also, am I the only one who cannot understand this, or am I the only
one who will ask the question? Does anybody else care? Would the
group prefer that I take this discussion private?