On Thu, 22 Jun 2000, Alex Yu wrote (slightly edited):
> ANOVA is said to be robust against assumption violations when the
> sample size is large. However, when the sample size is huge, it tends
> to overpower the test and thus the null may be falsely rejected.
> Which is a lesser evil? Your input will be greatly appreciated.
Hm. Well, those who argue that the null hypothesis is always false
anyway would doubtless consider that a proper outcome. ;-)
Are you saying, in effect, that (under some conditions) the precision of
the data exceeds the precision with which the null hypothesis is stated
(or intended to be stated)? Then at the outset you should devote some
attention to the precision you want to associate with the null, and
acknowledge that the current data have excessive power against the MUD
(minimum useful departure from the null); it follows that you are only
going to be interested in rejections of the null hypothesis for which
the effect size exceeds the MUD, and possibly even significantly exceeds
it. (You may want to direct a comment or two in the direction of
readers whose notion of MUD is smaller than yours.)
-- DFB.
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Donald F. Burrill [EMAIL PROTECTED]
348 Hyde Hall, Plymouth State College, [EMAIL PROTECTED]
MSC #29, Plymouth, NH 03264 603-535-2597
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