Mercurial > octave-nkf
diff scripts/statistics/tests/u_test.m @ 3454:d8b731d3f7a3
[project @ 2000-01-18 10:13:31 by jwe]
author | jwe |
---|---|
date | Tue, 18 Jan 2000 10:13:39 +0000 |
parents | f8dde1807dee |
children | 434790acb067 |
line wrap: on
line diff
--- a/scripts/statistics/tests/u_test.m Tue Jan 18 08:32:15 2000 +0000 +++ b/scripts/statistics/tests/u_test.m Tue Jan 18 10:13:39 2000 +0000 @@ -14,25 +14,25 @@ ## along with this file. If not, write to the Free Software Foundation, ## 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. -## usage: [pval, z] = u_test (x, y [, alt]) -## -## For two samples x and y, perform a Mann-Whitney U-test of the null -## hypothesis PROB(x > y) == 1/2 == PROB(x < y). Under the null, the -## test statistic z approximately follows a standard normal -## distribution. Note that this test is equivalent to the Wilcoxon -## rank-sum test. +## -*- texinfo -*- +## @deftypefn {Function File} {[@var{pval}, @var{z}] =} u_test (@var{x}, @var{y}, @var{alt}) +## For two samples @var{x} and @var{y}, perform a Mann-Whitney U-test of +## the null hypothesis PROB (@var{x} > @var{y}) == 1/2 == PROB (@var{x} +## < @var{y}). Under the null, the test statistic @var{z} approximately +## follows a standard normal distribution. Note that this test is +## equivalent to the Wilcoxon rank-sum test. ## -## 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 PROB(x > y) != 1/2. -## If alt is ">", the one-sided alternative PROB(x > y) > 1/2 is -## considered, similarly for "<". -## The default is the two-sided case. +## 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 +## PROB (@var{x} > @var{y}) != 1/2. If @var{alt} is @code{">"}, the +## one-sided alternative PROB (@var{x} > @var{y}) > 1/2 is considered, +## similarly for @code{"<"}. The default is the two-sided case. ## -## pval is the p-value of the test. +## 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 ## This implementation is still incomplete---for small sample sizes, ## the normal approximation is rather bad ...