Thanks Volkmar!!! I would try full factorial design...
> Dear Veronica,
>
> this sounds more complicated than most other flexible factorial
> designs I have seen so far. Your contrasts are probably not estimable
> because both group-by-sex and group-by-replication interaction columns
> are not orthogonal to the subject columns. Things would be much easier
> if you tried a full factorial design without an explicit subject factor.
>
> Volkmar
>
> Quoting Veronica Garcia Vazquez <[log in to unmask]>:
>
>> Dear list,
>>
>> We have problems with creating T-contrasts in my design. I would
>> appreciate any kind of help We receive...
>>
>> 1))) My conceptual design is the following one:
>>
>> |--Day 0: 9 images (1 image per
>> subject)
>> |--- VH (9 subjects) --- |
>> | |--Day 2: 9 images (1 image per
>> subject and same subjects as Day 0)
>> |-- Female----|
>> | | |--Day 0: 8 images (1 image per
>> subject)
>> | |--- CP (8 subjects) --- | |
>> |--Day 2: 8 images (1 image per subject and same subjects as
>> Day 0)
>> |
>> --|
>> | |--Day 0: 6 images (1 image per
>> subject)
>> | |--- VH (6 subjects) --- |
>> | | |--Day 2: 6 images (1 image per
>> subject and same subjects as Day 0)
>> |---- Male ---|
>> | |--Day 0: 7 images (1 image per
>> subject)
>> |--- CP (7 subjects) --- |
>> |--Day 2: 7 images (1 image per
>> subject and same subjects as Day 0)
>> 2))) In SPM5, we choose Flexible Factorial and 3 factors
>> in the following order: subject, group (for levels VH and CP),
>> replication (for levels Day 0 and Day 2) and sex (for levels female and
>> male).
>>
>> Subject: Independent Yes and Variance Equal
>> Group: Independent Yes and Variance UnEqual
>> Replication: Independent No and Variance UnEqual
>> Sex: Independent Yes and Variance UnEqual
>>
>> For example, for the two images (day 0 and day 2) of subject female VH,
>> its conditions are: 1 1 1; 1 2 1; For example, for the two images
>> (day 0 and day 2) of subject female CP, its conditions are: 2 1 1; 2
>> 2 1; For example, for the two images (day 0 and day 2) of subject
>> male VH, its conditions are: 1 1 2; 1 2 2; For example, for the
>> two images (day 0 and day 2) of subject male CP, its conditions are:
>> 2 1 2; 2 2 2; 3))) The main effects and interactions are:
>> Main effect: subject (1)
>> Interactions: group and replication (2 and 3); group and sex (2
>> and 4)
>>
>> 4))) We want to test main effect in sex (FEMALE>MALE)
>>
>> We tried with the t-contrasts: zeros(1,38) 1 1 -1 -1
>> 1/17*ones(1,17) -1/13*ones(1,13) zeros(8)
>> 1 1 -1 -1
>>
>> and they doesn´t work..., why?
>>
>> Regards
>>
>> Veronica
>>
>>
>>
>>
>>
>>
>>
>>
>>
>> my design is as follows:
>> 2 groups (N1, N2), 2 conditions (C1, C2). i specified 3 factors
>> (subject, group, condition) and got a design matrix comparable to
>> darrens and matts one (see attached file). the first 26 columns are for
>> the subjects, the last 4 columns are for the factor interactions
>> (N1xC1, N1xC2, N2xC1, N2xC2).
>>
>> so i want to have the following contrasts, which i managed to specify
>> in spm. my first question is:
>>
>> are the following contrast definitions correct?
>>
>>
>>
>>
>> i read the discussion in the list about the 2x2 ANOVA with great
>> interest, because i like to setup a similiar design. so i followed the
>> procedure of darren and matt for the flexible factorial design setup.
>> i designed 3 factors (subject (2xn), group (2 groups), condition (2
>> conditions) /independence yes, yes, no / variance equal, unequal,
>> unequal). specified the design by subject. for each subject of my group
>> 1 the condition matrix is [1 1;1 2], for each subject of my group 2 [2
>> 1;2 2]. There is a main effect of subject (factor number 1) and an
>> interaction of group x condition (factor numbers 2 3).
>> This produces a design very similiar to the ones of darren and matt. i
>> got n columns for my n participants, each with 2 rows. Now the
>> difference and my problem:
>> i got only 3 columns of group x condition instead of my expected 4.
>> these are column 1 (group1 x condition2), column 2 (group1 x
>> condition2), and column 3 (group2 x condition2). the lacking column
>> (group2 x condition1) seems to be mixed into column 2 (see attached
>> file). does anybody know what my mistake is?
>>
>> thanks markus
>
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