function t = studentize(x) % PURPOSE: If x is a vector, subtract its mean and divide%          by its standard deviation. If x is a matrix, %          do the above for each column.%---------------------------------------------------% USAGE:   out = studentize(x)% where:     x = a vector or matrix%---------------------------------------------------% RETURNS:%          out = transformed matrix% --------------------------------------------------% Written by KH (Kurt.Hornik@ci.tuwien.ac.at)  % Copyright Dept of Probability Theory and Statistics TU Wien% Documentation and code adapted from Octave% to matlab by J. LeSage      [nobs nvar] = size(x);    if nvar == 1    if (std(x) == 0)      t = zeros(size(x));    else      t = (x - mean(x)) / std(x);    end  elseif nvar > 1    l = ones (rows(x), 1);    t = x - l * mean(x);    tmp = [std(t)           ~any(t)];    t = t ./ (l * max (tmp));  else    error('studentize:  x must be a vector or a matrix');  end