GNU Octave - Local Sector 7 web page

Chapter 25: Statistics 213[pval, z] = z test (x, m, v, alt)Function FilePerform a Z-test of the null hypothesis mean (x) == m for a sample x from a normaldistribution with unknown mean and known variance v. Under the null, the teststatistic z follows a standard normal distribution.With the optional argument string alt, the alternative of interest can be selected. Ifalt 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) > mean (y) is used.Similarly for "