On Tue, 3 Apr 2007, Rick Froman went:

How would you interpret an ANOVA result where the F-test was
significant but none of the multiple comparisons were significant in
an HSD comparison?

Initially, I wrote a response as follows:

"Off the top of my head, I would say: An overall effect was detected,
but the sample sizes within individual cells were not sufficiently
large to attribute the effect to any specific pairwise comparison.

"Then I would talk, with due caution, about what it LOOKED like."

Then I did a Google search and found an explanation that's more
abstruse, but still seems to invoke the problem of small sample sizes:
<http://www.ats.ucla.edu/STAT/spss/library/manglm.htm> (scroll down to
the section "My tests don't agree!").  Note that the explanation does
*not* seem to be that you're missing "some more complicated contrast
among the means."

--David Epstein
  [EMAIL PROTECTED]

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