    function  [mean, stdev] = stat(x)    

    % STAT  Mean and standard deviation    
    %      For a vector x, stat(x) returns the     
    %      mean and standard deviation of  x.    
    %      For a matrix x, stat(x) returns two row vectors containing,    
    %      respectively, the mean and standard deviation of each column.    

    [m  n] = size(x);    

    if m == 1    
       m = n;     % handle case of a row vector     
    end    

    mean  = sum(x)/m;    
    stdev = sqrt(sum(x.^ 2)/m - mean.^2);
