Sounds to me as though you have in fact 5 within-subject variables:
the four you list plus
5) Replications (with 10 levels)
Of course, this is a random factor, whereas the other four are presumably
fixed factors, but presumably there's a way of telling GLM that. And
there is presumably no connection between Replication 1 in Colour and
Replication 1 in Shape (e.g.), (unless replications are numbered in
temporal order, in which case the factor can be interpreted as a practice
and/or fatigue factor) so interactions between Replications and the
other four factors are meaningless or uninterpretable, save as sources of
error variation for particular F-tests of the four binary factors and
their interactions.
Since you have required each subject to perform 160 times, there
might be some point to using the sequence number (1,...,160) as a
covariate, to control for an _overall_ fatigue or practice (or boredom!)
effect. Whatever merit this notion has may depend on whether the 10
replications for each combination of Colour/Shape/Pattern/Movement were
all massed (so to speak) at one time, or dispersed among the replications
for the other 15 cells; and on whether the sequence of replications by
combinations was the same for each of the 10 subjects, or differed from
subject to subject.
On Tue, 13 Jun 2000 [EMAIL PROTECTED] wrote:
> I have conducted an experiment with 4 within subject variables.
> 1) Colour
> 2) Shape
> 3) Pattern
> 4) Movement
>
> Each of these 4 factors have 2 levels so each subject would be exposed
> to 16 conditions in total. However, I have made each subject do 10
> replications per condition and I have 10 subjects so I have a total of
> 1600 data points.
>
> I have tried using SPSS repeated measures in GLM to analyse my data but
> I don't know how to include my replications. SPSS requires that I
> select 16 columns of dependant variables each representing a
> combination of my factors. However, I am only allowed one row per
> subject, so how do I input the 10 replications that each subject
> performed for each combination?
>
> Thanks !
>
> Alfred
>
>
>
>
>
> Sent via Deja.com http://www.deja.com/
> Before you buy.
>
>
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