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Firstly, we will rewrite the single-group study. One has for each
the GLM models:
|
(30) |
with
and
. The case of auto-correlation
will be examined later on. It is rather straightforward to
recognise the fixed effect in the following model:
|
(31) |
or
with obvious definitions for , and
with
.
One then derives easily the OLS for which gives the vector
of the OLS's from each model (30):
|
(32) |
Note that if one assumes that
then:
|
(33) |
which is the pooled estimate of variances, then:
|
(34) |
In either cases testing , with
, where is the contrast used on a
single model to assess the activation looked for, with the
statistic (19) will give the statistic used in
(4), and if is a matrix () containing more than
one contrasts the statistic (22) will be used.
Next: Random subject effect
Up: Multi-subject analysis with GLM
Previous: Multi-subject analysis with GLM
Didier Leibovici
2001-03-01