Hello,
I’m calculating the “test against baseline” of N×N imaginary coherence (the 68-scout Densikan-Killany atlas was used for N×N coherence). For the statistical settings, I used Bonferroni correction, and I checked signals, time, and frequency for “control over dims”. Frequency range was “78: 2: 92”. The time window was (-4.0000s, 4.0000s), and the baseline was (-4.0000s, -2.0005s).
I want to know how many time points, frequencies, and regions/edges were included in the correction. Can I get those information in the Matlab files?
Looking forward to your reply!
You can check this in the GUI, by opening the statistics matrix, then when you check/uncheck dimensions for the Bonferroni correction, a message is displayed in the Matlab command window, showing the number of repeated tests that are considered, and the corrected p-value threshold (or the average if there are multiple corrected p-thresholds, when not all the dimensions are selected):
BST> Average corrected p-threshold: 5.0549e-07 (Bonferroni, Ntests=98914)
https://neuroimage.usc.edu/brainstorm/Tutorials/Statistics#Correction_for_multiple_comparisons
@Raymundo.Cassani Thank you for replying!
Can I know the exact number of “signals, time, and frequency“ being used in calculation?
Yes, you can know this by correcting for each of those dimensions alone and see the command window.
Keep in mind that for NxN coherence, the correction of "signals" is not really the channels, but the unique coherence pairs. Since coherence is a symmetric metric, the number of unique pairs is calculated as:
% Number of signals
nSignals = 68;
% Elements in coherence matrix
nElemCohMatrix = nSignals * nSignals;
% 4624
% Removing the self-connectivity elements, i.e., diagonal
nElemCohMatrixNoSelf = nElemCohMatrix - nSignals;
% 4556
% Since coherence is symmetric, upper triangle and lower triangle are the same
% so only half of nElemCohMatrixNoSelf are unique
nElemCohMatrixNoSelfUnique = nElemCohMatrixNoSelf / 2;
% 2278