Statistical Analysis

Hi all.

I am quite new to REST and SPM, so my question might sound silly.

I want to do statistical analysis on ReHo and ALFF maps. I watched the DPARSF course videos and it says that in order to perform Statistical analyisis (One- Sample t Test), I have to calculate mReHo-1. 

correct me if I am wrong, It means that the null hypothesis would be : mReho-1 = 0. Which in turn means that I would be looking for voxels in which mReho is greater than one. 

I do not quite get the theory behind this... why not compare the results with 0 instead of 1? 

I appreciate any help.


mReHo has an average value of 1, by finding those voxels has mReHo bigger than 1, those are voxels higher than the global mean. You can also find those voxels has value lower than the global mean.

As mReHo is always bigger than 0, if you compare with 0, they you will have all the brain.