Dear Will and Seyed,
On the same subject may I ask what is meant by "prior hypotheses" here? For
example, suppose
(1) you run the images of a group of subjects and you find an activation at
x, y, z.
(2) then on a closer look at your original data you realize that in your
covariate measurements (i.e. the task score) you have an outlier
(3) then you redo the analysis without including the subject who was an
outlier on the cognitive score
now, you know exactly where you want the activation (from step one above you
got an activation and you would like to have it in the same place). but is
this really a prior hypothesis? in other words: does one you need to use the
corrected p-values or not? i am asking because i am in a discussion with
someone about this question. i would personally think that this would be a
false approach since you made your hypothesis on a finding which may have
been corrupted by the outlier. but then again i might be wrong and in
practice it works out fine.
Thanks in advance for comments (references to books or articles are also
welcome),
Zoltan
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Zoltan Nagy
Karolinska Institutet
Neonatology
Astrid Lindgrens Barnsjukhus Q2:07
171 76 Stockholm, Sweden
Phone: +46-8-517-77354
Fax: +46-8-517-77353
E-mail: [log in to unmask]
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