In article <[EMAIL PROTECTED]>,
dennis roberts <[EMAIL PROTECTED]> wrote:
>At 03:45 PM 10/9/01 -0400, Wuensch, Karl L wrote:
>>Some of those who think that estimation of the size of effects is more
>>important than the testing of a nil hypothesis of no effect argue that we
>>would be better served by reporting a confidence interval for the size of
>>the effect. Such confidence intervals are, in my experience, most often
>>reported in terms of the original unit of measure for the variable involved.
>>When the unit of measure is arbitrary, those who are interested in
>>estimating the size of effects suggest that we do so with standardized
>>estimates. It seems to me that it would be useful to present confidence
>>intervals in standardized units.
>why? you only get further away from the original data scale/units you are
>working with ...
>in what sense ... is ANY effect size indicator anything BUT arbitrary? i
>don't see how trying to standardize it ... or any confidence interval ...
>makes it anything other than still being in arbitrary units ...
>i would argue that whatever the scale is you start off using ... that is as
>CLOSE as you can get to the real data ... even if the scale does not have
>any "natural" or "intuitive" kind of meaning
>standardizing an arbitrary variable does NOT make it more meaningful ...
>just like converting raw data to a z score scale does NOT make the data
>more meaningful
>standardizing a variable may have useful properties but, imputing more
>meaning into the raw data is not one of them
Furthermore, standardizing on almost anything makes it
impossible to compare different populations, where the
location and scale, or other relevant parameters, may be
different. It also makes asymptotic theory much more
complicated, as the effects of non-normality are usually
much greater if the standardization is used.
--
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
=================================================================
Instructions for joining and leaving this list and remarks about
the problem of INAPPROPRIATE MESSAGES are available at
http://jse.stat.ncsu.edu/
=================================================================
