% -*- texinfo -*-
% @deftypefn {Function File} {[@var{pval}, @var{t}, @var{df}] =} welch_test (@var{x}, @var{y}, @var{alt})
% For two samples @var{x} and @var{y} from normal distributions with
% unknown means and unknown and not necessarily equal variances,
% perform a Welch test of the null hypothesis of equal means.
% Under the null, the test statistic @var{t} approximately follows a
% Student distribution with @var{df} degrees of freedom.
%
% With the optional argument string @var{alt}, the alternative of
% interest can be selected. If @var{alt} is @code{'~='} or
% @code{'<>'}, the null is tested against the two-sided alternative
% @code{mean (@var{x}) ~= @var{m}}. If @var{alt} is @code{'>'}, the
% one-sided alternative mean(x) > @var{m} is considered. Similarly for
% @code{'<'}, the one-sided alternative mean(x) < @var{m} is
% considered. The default is the two-sided case.
%
% The p-value of the test is returned in @var{pval}.
%
% If no output argument is given, the p-value of the test is displayed.
% @end deftypefn