"Chung" wrote in message
...
Harry Lavo wrote:
"John Corbett" wrote in message
...
In article , "Harry Lavo"
wrote (re
http://www.hfm-detmold.de/eti/projek...paper_6086.pdf):


It is certainly a test that probably is as good an abx test as could be
done.

Huh?


Meaning, they paid attention to most details.

Are there any details that they missed?


Yes, they didn't do the follow up tests. And they allowed communication
between the tests.



The authors are obviously believers in abx. Accordingly they downplay
the
fact that there are differences as evidenced by four responders.

Four listeners getting at least 15 of 20 correct in 145 attempts is
hardly
strong evidence. Is there any other evidence to support this "fact"
that
there are differences?


See below.

Consider these facts:

For a single run of 20 trials, the probability that someone would get at
least 15 correct just by guessing is .0207, which is about 1 chance in
48.

In an experiment with 145 runs (of 20 trials each) the expected number
of
apparently significant results (at the .05 level) is 3 if subjects are
just guessing. That is, over all such experiments, the average number
of
20-trial runs with "significant" results is 3 per 145-attempt
experiment.

The probability that just guessing in an experiment with 145 attempts to
get 15 or more correct in 20 trials would yield at least 4 successes is
about .3529, so seeing four apparently successful results is not unusual
enough to rule out chance.

I didn't rule out chance...

Well, Harry, you have to understand what you wrote. Here is what you
wrote:

"Accordingly they downplay the fact that there are differences as
evidenced by four responders."

You said that it is a fact that there are differences. No, you ruled out
chance, Harry.

There *were* differences...the issue is whether or not they were due to
chance.
They outline all the reasons the differences were suspect, and their
conclusion virtually ignores that apparently there was a difference. I'll
stand by my statement, and the alternative conclusions that would have been
more accurate.