% -*- 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

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