: [pval, z] = z_test (x, m, v, alt)

Perform a Z-test of the null hypothesis mean (x) == m for a sample x from a normal distribution with unknown mean and known variance v.

Under the null, the test statistic z follows a standard normal distribution.

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 along with some information.

Package: statistics