Dear list,

we have several difficulty to understand how I should build fsdg file and we are worried to produce correct results.

On FS site, it is not available an example if we would look for differences among 4 different groups (A, B, C, D;  4 Groups - One Factor/Three Levels - No Covariates).

The proposed design with 2 levels and 2 factors is no helpful in our case.

We have 4 groups (1 factor and 4 levels, no covariates) and we our hypothesis (in term of impaiment) is A<B<C<D.

Which should be the group.effect.mtx?

How should we look to difference between Group1, Group2, Group3 and Group4?

Should we opt for G1+G3 vs G2+G4 or G1+G2 vs G3+G4? Other option?

Please may you argue a rationale?

e.g. Looking your example on three Groups (One Factor/Three Levels), No Covariates, we wonder why if Normals==MCI AND Normals==AD, then it MUST be the case that MCI==AD?

We aim at assess differences by using more complex design (4x2x4), including 

4 different structures, looking at right and left structures and having 4 levels (4 different groups).

How should we do, please?

Thank you very much.

Best regards

Stefano