On 7/26/07, Steve Smith <[log in to unmask]> wrote:

Hi Sophie, yes you're probably right that 2x3 isn't quite the same as
3x2, although presumably the difference really only comes down to
which set of options you want to describe different factors and
levels as fixed or random (see for example the table at the bottom of
http://www.fmrib.ox.ac.uk/fsl/feat5/detail.html#ANOVA3factors2levels ).

Hello Steve

And thank you for replying to my question. I am sorry however, but

I must disagree with you! As I understand it a 2 factor by 3 level design

(2x3) is *very* different from a 3 factor by 2 level design (3x2). The former

involves 6 unique conditions, the latter 8 (2x2x2). Hence, no simple

rearrangement or relabelling from fixed to random can map 6 to 8

dimensions. More particularly, for a FEAT setup, the latter can be

modelled by binary classications in the structure of the FEAT design

matrix, making it easy to do intra-level comparisons. The former cannot,

as it is it necessary to do separate events for each level.

I'm afraid that the number of possibilities for ANOVA designs is
endless so we can't provide examples for all of them!

Of course I must sympathise with your positition! But I am so very

stuck at the moment as I just cannot get my head around this. I just

do not see how to make the design matrix for such a higher order model.

I guess from the later post of at least one other person (Kristofer Kinsey)

I am not alone!

So rather than asking for all possible examples, please please please

could you provide ONE example of a higher order ANOVA where there

is more than 1 factor (e.g. 2) and these factors are at more than 2 levels

(e.g. 3)? I think the simplest example of this is the 2x3 design (and yes

I know this is what I originally asked for but feel free to give a better

example if it is more helpful)...

merci

Sophie