--- In vpFREE@yahoogroups.com, "Harry Porter" <harry.porter@v...>
wrote:
Harry Porter wrote:
> > However, it occurs to me that there may be a problem with
> > suggesting that given an adverse outcome (the $340 loss, in
your
> > example) that has less than a 2% likelihood, you'd have less
than
> > a 2% confidence in the machine's fairness.
iggy replied:
> well, that's what 2% means
> if you want 1% or some other arbitrary number, you can certainly
> modify the procedure to your liking
Iggy, I think the best case here is that we're going to agree to
disagree with each other -- strongly.
Extending your logic -- I might ask, once the determination is made
that there's over a 98% likelihood that the machine is biased,
what's
the most likely amount of that bias? Your interpretation would lead
me to decide that it's most likely that the machine is negatively
biased by 8% to 9%, based upon this single trial, since that's the
bias that would most likely produce this session result.
now you're asking for more conclusions, not only do you want to
determine if a machine is biased, you want to know by what amount?
that's a much more complex issue, you have to know the variance of
your 2000 hand result as well as the average return ... then you've
got what in statistics they call sampling ...
Correct me, if you see it otherwise.
I then see you suggesting that I should reasonably proceed to the
casino commission with my evaluation and tell them that the machine
is
likely gaffed, most probably by more than 8%. (Understand that I
have
a problem saying the machine is gaffed if I can't quantify it more
strongly than "by at least a fraction of a percent, and probably
more".)
just tell them you suspect it is gaffed, let them determine if it
really is and by what amount
that's their job, if you insist you can do further studies, but why?
is it worth it?
once you suspect a machine is even 1% less than it should be, is it
really worth determining how bad it is? personally i would just report
it and move on
in my book a gaffed machine isn't playable, i don't really care by how
much it's gaffed
(excluding a few rare cases where a consistent gaff was beatable with
strategy modification)
it's the same as blackjack, if i know a dealer is dealing seconds, i
don't really care how often they are doing it and on what hands
likewise, legally, a gaffed machine is a gaffed machine, the amount of
gaffing has no legal results
If I'm on track in what you're saying by implication, I won't deem
it
"silly", as jay did. But I will say that it's not reasonable.
If it should be the case that I'm misreading/distorting what you've
said, I'm not sure it's productive the explore this further, But
until I understand otherwise, I'm not able to accept your extension
of
the probability of a given result to a precise statement of
confidence
in machine fairness/unfairness.
- Harry
on the topic of gaffs, in "All the Best of Video Poker Times" by Dan
Paymar, there is a report of fixed blackjack machines at a Rhode
Island racetrack, the player noticed the dealer got blackjack with an
ace more than random results would allow, the player wisely altered
strategy and always took insurance and beat the machines badly