¥1-Way ANOVA
HProgram
3dANOVA
åDetermine
whether treatments (levels) of a single factor (independent parameter) has an effect on the measured response
(dependent parameter, like FMRI percent signal change due to some stimulus).
åExamples
of factor: subject type, task type, task difficulty, drug type,
drug dosage, etc.
åWithin
a factor are levels: different sub-categorizations
íExample:
factor=subject type; level 1=normals, level 2=patients with mild symptoms, level 3=patients with severe symptoms
åThe
various AFNI ANOVA programs differ in the number of factors they allow: 3dANOVA
allows 1 factor, comprising up to
100 levels
HAssumptions
åValues
are normally distributed
åNo
assumptions about relationship between dependent and independent variables (e.g., not necessarily linear)
åIndependent
variables are qualitative
HCan
also use 3dttest if there are
only two levels
åThe
1-way 3dANOVA analysis is a
generalization to multiple levels of an unpaired 3dttest
(for generalization of paired, wait for 3dANOVA2)
HExample:
r different types of subjects performed the same task in the scanner