I would use 2 models.
Model 1: Controls/Patients, TreatmentA, levels 1-4 (3 factors: Group,
levels, subjects)
Model 2: Controls, TreatmentA/B, levels 1-4 (3 factors: Treatment,
levels, subjects)
For the latter, I'd use GLM Flex, which will give you the partitioned
error term for each within-subject measure. Also, remember that any
between-subject effect (e.g. Group effects or individual treatment or
levels) is statistically invalid in SPM. In GLM Flex thatose
comparisons are statistically valid.
Best Regards, Donald McLaren
=================
D.G. McLaren, Ph.D.
Research Fellow, Department of Neurology, Massachusetts General Hospital and
Harvard Medical School
Postdoctoral Research Fellow, GRECC, Bedford VA
Website: http://www.martinos.org/~mclaren
Office: (773) 406-2464
=====================
This e-mail contains CONFIDENTIAL INFORMATION which may contain PROTECTED
HEALTHCARE INFORMATION and may also be LEGALLY PRIVILEGED and which is
intended only for the use of the individual or entity named above. If the
reader of the e-mail is not the intended recipient or the employee or agent
responsible for delivering it to the intended recipient, you are hereby
notified that you are in possession of confidential and privileged
information. Any unauthorized use, disclosure, copying or the taking of any
action in reliance on the contents of this information is strictly
prohibited and may be unlawful. If you have received this e-mail
unintentionally, please immediately notify the sender via telephone at (773)
406-2464 or email.
On Wed, Oct 31, 2012 at 9:09 AM, SUBSCRIBE SPM Veda
<[log in to unmask]> wrote:
> Dear SPM experts,
>
> I have a question regarding how to model unbalanced factors in second level.
> In experiment, there are three variables: group (normal vs. patient), treatment (A vs. B) and level (1-4). The problem is that only the normal group went through both treatment A (level1-4) and B (level1-4) while the patient group went through treatment A. How can I model all these data in one design matrix at the second level?
> Any suggestion is appreciated! Thanks!
>
> Sincerely,
> Veda
|