% -*- texinfo -*- % @deftypefn {Function File} {[@var{pval}, @var{t}, @var{df}] =} t_test_2 (@var{x}, @var{y}, @var{alt}) % For two samples x and y from normal distributions with unknown means % and unknown equal variances, perform a two-sample t-test of the null % hypothesis of equal means. Under the null, the test statistic % @var{t} 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}) ~= mean (@var{y})}. If @var{alt} is @code{'>'}, % the one-sided alternative @code{mean (@var{x}) > mean (@var{y})} is % used. Similarly for @code{'<'}, the one-sided alternative @code{mean % (@var{x}) < mean (@var{y})} is used. 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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