% -*- texinfo -*-
% @deftypefn {Function File} {} kurtosis (@var{x}, @var{dim})
% If @var{x} is a vector of length @math{N}, return the kurtosis
% @tex
% $$
% {\rm kurtosis} (x) = {1\over N \sigma(x)^4} \sum_{i=1}^N (x_i-\bar{x})^4 - 3
% $$
% where $\bar{x}$ is the mean value of $x$.
% @end tex
% @ifnottex
%
% @example
% kurtosis (x) = N^(-1) std(x)^(-4) sum ((x - mean(x)).^4) - 3
% @end example
% @end ifnottex
%
% @noindent
% of @var{x}. If @var{x} is a matrix, return the kurtosis over the
% first non-singleton dimension. The optional argument @var{dim}
% can be given to force the kurtosis to be given over that
% dimension.
% @end deftypefn