Mercurial > octave-antonio
view scripts/statistics/tests/chisquare_test_independence.m @ 19833:9fc020886ae9
maint: Clean up m-files to follow Octave coding conventions.
Try to trim long lines to < 80 chars.
Use '##' for single line comments.
Use '(...)' around tests for if/elseif/switch/while.
Abut cell indexing operator '{' next to variable.
Abut array indexing operator '(' next to variable.
Use space between negation operator '!' and following expression.
Use two newlines between endfunction and start of %!test or %!demo code.
Remove unnecessary parens grouping between short-circuit operators.
Remove stray extra spaces (typos) between variables and assignment operators.
Remove stray extra spaces from ends of lines.
author | Rik <rik@octave.org> |
---|---|
date | Mon, 23 Feb 2015 14:54:39 -0800 |
parents | 4197fc428c7d |
children |
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## Copyright (C) 1995-2015 Kurt Hornik ## ## This file is part of Octave. ## ## Octave is free software; you can redistribute it and/or modify it ## under the terms of the GNU General Public License as published by ## the Free Software Foundation; either version 3 of the License, or (at ## your option) any later version. ## ## Octave is distributed in the hope that it will be useful, but ## WITHOUT ANY WARRANTY; without even the implied warranty of ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU ## General Public License for more details. ## ## You should have received a copy of the GNU General Public License ## along with Octave; see the file COPYING. If not, see ## <http://www.gnu.org/licenses/>. ## -*- texinfo -*- ## @deftypefn {Function File} {[@var{pval}, @var{chisq}, @var{df}] =} chisquare_test_independence (@var{x}) ## Perform a chi-square test for independence based on the contingency ## table @var{x}. Under the null hypothesis of independence, ## @var{chisq} approximately has a chi-square distribution with ## @var{df} degrees of freedom. ## ## The p-value (1 minus the CDF of this distribution at chisq) of the ## test is returned in @var{pval}. ## ## If no output argument is given, the p-value is displayed. ## @end deftypefn ## Author: KH <Kurt.Hornik@wu-wien.ac.at> ## Description: Chi-square test for independence function [pval, chisq, df] = chisquare_test_independence (x) if (nargin != 1) print_usage (); endif [r, s] = size (x); df = (r - 1) * (s - 1); n = sum (sum (x)); y = sum (x')' * sum (x) / n; x = (x - y) .^2 ./ y; chisq = sum (sum (x)); pval = 1 - chi2cdf (chisq, df); if (nargout == 0) printf (" pval: %g\n", pval); endif endfunction