while this may be the case ... in general ... for some decisions we make
... we would not even allow this level of snickering to suggest to us that
something is afoul ... whereas for others ... it would not bother us (or
should not) if the chances were larger ...
it all depends ...
At 10:36 AM 10/23/00 -0400, David Evans wrote:
>I remember seeing the same thing a year or so ago on this list. I tried
>it for the first time this semester with my "refresher" course in
>statistics for a class of incoming graduate students. I tossed a coin a
>number of times and reported the result as "heads" each time
>irrespective of the actual outcome. At the third call a slight snigger
>went round the room, clearly emerging disbelief at the fourth and
>outright disbelief at the fifth, corresponding to p values of 0.125,
>0.0625, 0.03215 based on a hypothesis of a fair coin and a truthful
>instructor. It appears, indeed, that 0.05 reasonably represents the
>level at which human scepticism begins to emerge.
>
>David Evans
>School of Marine Science
>College of William & Mary
>Gloucester Point, VA
>
>"John W. Kulig" wrote:
> >
> > I have been searching for some "psychological" data on the .05
> issue - I
> > know it's out there but haven't found it yet. It went something like this:
> > Claim to a friend that you have a fair coin. But the coin is not fair.
> Flip the
> > coin (you get heads). Flip it again (heads again). Ask the friend if
> s/he wants
> > to risk $100 (even odds) that the coin is not fair. At what point does the
> > friend (who is otherwise ignorant of p issues) wager a bet that the
> coin is not
> > fair? I have heard that after 5 or 6 heads the friend is pretty sure
> it's a bad
> > coin - or at least a trick (at this point we cross .05 on the binomial
> chart)
> > .05 may be rooted in our general judgment/perception heuristics -
> > understandable in evolutionary terms if we examine the everyday
> situations we
> > make these judgments in. Of course the relative risks of I versus II would
> > matter (e.g. falsely accusing and starting a brawl vs. losing to a con
> artist).
> > I will try to locate some research data on this .... or I'll flip a few
> coins
> > in my next statistically naive class.
> >
> > --
> > ---------------------------------------------------------------
> > John W. Kulig [EMAIL PROTECTED]
> > Department of Psychology http://oz.plymouth.edu/~kulig
> > Plymouth State College tel: (603) 535-2468
> > Plymouth NH USA 03264 fax: (603) 535-2412
> > ---------------------------------------------------------------
> > "What a man often sees he does not wonder at, although he knows
> > not why it happens; if something occurs which he has not seen before,
> > he thinks it is a marvel" - Cicero.
> >
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