GJP_revisited/median_ci.m

function [output] = median_ci(data,nBS,quantileBS)
% MEDIAN_CI computes median and confidence interval of the median using bootstrap method
% Syntax:    [output] = median_ci(data,nBS,quantileBS)
% Example: 
%     data = [1 1 1 1 1; 2 2 2 2 2; 3 3 3 3 3];
%     nBS=1000;
%     quantileBS = 0.5;
%     [output] = median_ci(data,nBS,quantileBS)


nsubj = size(data,1);
nlevel = size(data,2);
quantileBS=1-quantileBS;
quantileBS = [quantileBS/2 1-quantileBS/2];

output = NaN(3,nlevel);
output(2,:) = median(data,1);

for l=1:nlevel    
    temp = data(:,l);
    medianBS = NaN(nBS,1);
    for b=1:nBS
        medianBS(b) = median( datasample(temp,length(temp)) );
    end
    output([1 3],l) = quantile(medianBS,quantileBS);
end