% -*- texinfo -*-
% @deftypefn {Function File} {[@var{pval}, @var{z}] =} z_test (@var{x}, @var{m}, @var{v}, @var{alt})
% Perform a Z-test of the null hypothesis @code{mean (@var{x}) ==
% @var{m}} for a sample @var{x} from a normal distribution with unknown
% mean and known variance @var{v}. Under the null, the test statistic
% @var{z} follows a standard normal distribution.
%
% 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 @code{mean (@var{x}) > @var{m}} is considered.
% Similarly for @code{'<'}, the one-sided alternative @code{mean
% (@var{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
% along with some information.
% @end deftypefn