Hello Spharm experts, 

I am currently running shapeAnalysisMANCOVA on my hippocampal data. Everything is going along smoothly in my examination of a statistically significant main effect of group (diagnosis) and I have just a few questions on how to move forward.

My input .csv file has the following variables/headings:
diagnosis,scaling,inputfile,sex,totalbrainvolume,age

...and I am running the following command to obtain a significant main effect of group, while accounting for sex, totalbrainvolume and age:

shapeAnalysisMANCOVA input.csv --infileColumn 2 --numGroupTypes 2 --numIndependent 2 --columnGroupTypes 0,3 --columnIndependent 4,5

My questions are as follows:

1. how can I explicitly model the interaction of diagnosis and sex, while controlling for totalbrainvolume and age?

2. is there a singular overall p value that is produced by shapeAnalysisMANCOVA that would be similar to the significance of an omnibus test? I'm a bit confused as to how correction for multiple comparisons is performed. I see that FDRP and Bonferroni text files are produced. But can one report that a statistically significant difference exists if the clusters in the FDRP and Bonferroni files are exceptionally small?

3. In visualizing the magnitude of structural differences between two groups, it's my understanding that I should load and view the *_meanAll.vtk file which happens to have various attributes already embedded within it (including "DiffMagnitude" and "DiffMagnitude_original"). The DiffMagnitude_original attribute has values ranging from -3.22 to 3.52, whereas the "DiffMagnitude" has a range of 0 to 100. Can you tell me what these values indicate (including their units)?

4. do I need to mean center my continuous covariates prior to running shapeAnalysisMANCOVA? I see that this question was previously raised by another user, but the answer was not clear.

Many thanks in advance for the help!
Lara