https://github.com/MICA-MNI/micaopen/
Tip revision: d3988d51e01940007595761dab6b846ce2506433 authored by boyongpark on 11 March 2021, 01:38:19 UTC
Update grp_comparison.m
Update grp_comparison.m
Tip revision: d3988d5
mica_zdiff.m
function [corrdiff, p] = mica_zdiff(r1,r2,n1,n2)
% computes the differernce of 2 correlation coefficients
% Usage:
% [corrdiff, p] = mica_zdiff(r1,r2,n1,n2)
%
% Input
% r1 and r2 are the correlation coefficients in group 1 and 2 respectively
% n1 is size of group 1, n2 is size of group 2
%
% Output:
% corrdiff is the z stat, p is the two tailed p value
%
% taken from
% FISHER, R. A., 1921: On the ęprobable errorė of a coefficient of
% correlation deduced from a small sample. Metron 1, 1-32.
% function has been tested against:
% http://faculty.vassar.edu/lowry/rdiff.html
% boris@bic.mni.mcgill.ca, Dec 2008
z1 = 1/2 * log( (1+r1) ./ (1-r1) );
z2 = 1/2 * log( (1+r2) ./ (1-r2) );
corrdiff = (z1 - z2) ./ sqrt( 1/(n1-3) + 1/(n2-3) );
p = 2*(1-normcdf(abs(corrdiff)));