I recently realized that there's a point that I was unclear about when setting up a paired samples T-test in SPM5 or SPM8.  When setting up this test, do the Indepedent and Variance options apply to the subjects or are they applied to the paired conditions?  If I was setting this up in a flexible factorial model, I would have explicit Subject and Condition factors, each of which would have separate Independent/Variance options to set, and I would typically set Subject to Independent, Equal Variance and set Condition to Dependent, Equal Variance.  

But when setting up a Paired T-test, one of these factors must be set implicitly by SPM, so I'm left wondering which I should be setting the options for, Subject or Condition?



-Mike Angstadt
(734) 936-8229
Research Area Specialist / PANLab Lab Manager
Department of Psychiatry / University of Michigan

Electronic Mail is not secure, may not be read every day, and should not be used for urgent or sensitive issues