In article <[EMAIL PROTECTED]>,
dennis roberts <[EMAIL PROTECTED]> wrote:
>At 01:16 PM 4/10/00 -0300, Robert Dawson wrote:
>>both leave the listener wondering "why 0.5?" If the only answer is "well,
>>it was a round number close enough to x bar [or "to my guesstimate before
>>the experiment"] not to seem silly, but far enough away that I thought I
>>could reject it." then the test is pointless.
-Robert Dawson
>YOU HAVE made my case perfectly! ... this is why the notion of hypothesis
>testing is outmoded, no longer useful ... not worth the time we put into
>teaching it ...
>in the case above ... i would ask:
There are cases where .5 makes sense, or rather
approximately .5 makes sense. This happens in genetic
regression, if one assumes additivity, random mating, and
the contributions of the parents are equal. However,
Rubin's second commandment is that thou shalt not believe
thy assumptions.
The problem of testing approximate hypotheses is more
difficult. From a decision-theoretic standpoint, if
the width of the acceptance region in the parameter
space is small compared to the standard error of the
usual estimator, one can use a point null as a good
approximation. If not, the users assumptions become
more important.
--
This address is for information only. I do not claim that these views
are those of the Statistics Department or of Purdue University.
Herman Rubin, Dept. of Statistics, Purdue Univ., West Lafayette IN47907-1399
[EMAIL PROTECTED] Phone: (765)494-6054 FAX: (765)494-0558
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