LLN, le 16/02/06
Dear Luca,
Methodologically speaking, I guess it would be better to scan your
control group also 3 times. You will then have an "easy" 3(time) *
2(groups) Anova.
As concerns the weight of your contrasts, have a look at
<http://www.jiscmail.ac.uk/cgi-bin/wa.exe?A2=ind03&L=SPM&D=0&I=-3&P=231918>
(mail from Jesper Andersson Thu, 12 Jun 2003 ).
Hope this helps,
Mauro.
>I have a group(15 subjects) of patients with 3 time-point (0, 1, 2) and a
>group of controls(15 subjects). My hypothesis is that the group of
>patients has a progressive increase of the BOLD activity from the first
>time point to the third with respect to controls.
>What kind of ANOVA model (4 groups) can I use?
>
>first contrast:
>control(+3), patient group time-point 0(+1),patient group time-point 1
>(-1),patient group time-point 2(-3)
>
>second contrast:
>control(-3), patient group time-point 0(-1),patient group time-point 1
>(+1),patient group time-point 2(+3)
>
> OR
>
>first contrast:
>control(-9), patient group time-point 0(+1),patient group time-point 1
>(+3),patient group time-point 2(+5)
>
>second contrast:
>control(+9), patient group time-point 0(-1),patient group time-point 1
>(-3),patient group time-point 2(-5)
>
>Thanks
>LP
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Mauro PESENTI
Research Associate, National Fund for Scientific Research (Belgium)
Unite de Neurosciences Cognitives
Departement de Psychologie
Universite Catholique de Louvain
Place Cardinal Mercier, 10
B-1348 Louvain-la-Neuve
tel.: +32 (0)10 47 88 22
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http://www.nesc.ucl.ac.be
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