Date: Tue, 5 Nov 1996 13:09:22 -0500
Reply-To: "William B. Ware" <wbware@EMAIL.UNC.EDU>
Sender: "SPSSX(r) Discussion" <SPSSX-L@UGA.CC.UGA.EDU>
From: "William B. Ware" <wbware@EMAIL.UNC.EDU>
Subject: Re: Adjustment factors when using two-factor experiments with
Are you referring to adjusted F-statistics, or adjusted F-values. The use
of the F-distribution (F-values) in repeated measures designs is
predicated on some rather restrictive assumptions regarding the nature of
the variance-covariance matrix of the repeated measures. If that
assumption is violated, then one may adjust the df using the results of
Geisser and Greenhouse. This adjustment assumes a "maximum" violation.
However, one can estimate the degree to which the assumption is violated
and calculate a "constant" that is used to adjust the df for that
particular situation. This "exact" adjustment is available in the SPSS
Manova procedure using either of the two "epsilons".
William B. Ware, Professor and Chair Educational Psychology
CB# 3500 EMAIL: email@example.com
University of North Carolina PHONE: (919)-966-5266
Chapel Hill, NC 27599-3500 FAX: (919)-962-1533
On Tue, 5 Nov 1996, Mike Broyles wrote:
> I note that adjusted F-values are sometimes used in repeated measures
> when certain conditions are not met. How does one determine as to when
> adjusted values should be used?
> Mike Broyles