Jamie Johnston johnston at KIN.UCALGARY.CA
Sun May 3 20:00:19 CEST 2009

Hi all -
I am trying to run a monte carlo - indepsamplesZcoh - cluster on my data
using freqstatistics.  I input two data files into freqstatistics with
the cohspctrm having dimensions 2 (subjects) x 10 (channels, # of
coherence spectra) x 52 (frequencies).  I run into a dimension mismatch
in the function clusterstat.  If I run any other statistic (i.e.,
indepsamplesT) it runs fine.  When running the indepsamplesT,
clusterstat receives two inputs: statobs (520x1) and statrnd (520x100).
These dimensions make sense to me.  However, when running
indepsamplesZcoh these two variables have dimensions 2340x1 and
2340x100, respectively.  This happens around lines 104-108 in
indepsamplesZcoh.m with computation of the variables "chancmbsel" and
"nnewsamples."  I'm not understanding what these variables do, but my
guess is that I need to setup my data files differently in the
beginning.  My understanding of what this analysis protocol does is
compute the z-statistic on each channel of coherence data (10 for each
data file) and then find the difference between the z-statistic for each
channel across the data files.  Once this is complete it runs the
permutations to determine the significance.
Please verify that what I have done is correct and any help with the
error I am getting would be greatly appreciated.
Jamie Johnston, Ph.D.
Assistant Professor
Faculty of Kinesiology
University of Calgary
2500 University Dr. NW
Calgary, AB
T2N 1N4
Phone: +1 (403) 220-3649
Fax: +1 (403) 284-3553
email: johnston at

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