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: [pval, t, df] = welch_test (x, y, alt)

For two samples x and 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 t approximately follows a Student distribution with df degrees of freedom.

With the optional argument string alt, the alternative of interest can be selected. If alt is "!=" or "<>", the null is tested against the two-sided alternative mean (x) != m. If alt is ">", the one-sided alternative mean(x) > m is considered. Similarly for "<", the one-sided alternative mean(x) < m is considered. The default is the two-sided case.

The p-value of the test is returned in pval.

If no output argument is given, the p-value of the test is displayed.

Package: octave