I am just tossing in my two cents worth ...
On Thu, 15 Feb 2001 07:53:13 GMT, Jim Steiger, posting as
[EMAIL PROTECTED] (Irving Scheffe) wrote:
< snip, name comment >
> 2. I tried to make the Detroit Pistons example as obvious as I could.
> The point is, if you want to know whether one population performed
> better than another, and you have the performance information, [under
> the simplying assumption, stated in the example and obviously not
> literally true in basketball, that you have an acceptable
> unidimensional index of performance], you don't do a statistical test,
> you simply compare the groups.
- and if you want to know something about how unlikely it was to
get means that extreme, you can randomize. Do the test.
>
> Your question about the randomization test seems
> to reflect a rather common confusion, probably
> deriving from some overly enthusiastic comments
> about randomization tests in some
> elementary book.
- If you are willing, perhaps we could discuss the textbook
examples. I don't remember seeing what I would call
"overly enthusiastic comments about randomization."
When I looked a few years ago, I did see one book with an
opposite fault, exemplified in a problem about planets.
I thought the authors' were pedantic or silly, when they refused
to admit randomization as a first step of assessing whether there
*might* be something interesting going on.
> Some people seem to
> emerge with vague notions that two-sample randomization tests make
> statistical testing appropriate in any situation in which you have
> two stacks of numbers. That obviously isn't true.
> Your final question asks if "statistical tests" be appropriate
> even when not sampling from a population. In some sense, sure. But not
> in this case.
I can't say that I have absorbed everything that has been argued.
But as of now, I think Gene has the better of it. To me, it is not
very appropriate to be highly impressed at the mean-differences,
when TESTS that are attempted can't show anything. The samples
are small-ish, but the means must be wrecked a bit by outliers.
>
> Maybe the following example will help make
> it clearer:
< snip rest, including example that brings in "power" but not
convincingly. >
--
Rich Ulrich, [EMAIL PROTECTED]
http://www.pitt.edu/~wpilib/index.html
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