/usr/share/octave/packages/nan-3.1.4/ttest2.m is in octave-nan 3.1.4-3.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 | function [h, pval, ci, stats, df] = ttest2 (x, y, alpha, tail, vartype, DIM)
% TTEST2 (unpaired) t-test
% For two samples x and y from normal distributions with unknown
% means and unknown equal variances, perform a two-sample t-test of
% the null hypothesis of equal means. Under the null, the test
% statistic T follows a Student distribution with DF degrees of
% freedom.
%
% TTEST2 treads NaNs as "Missing values" and ignores these.
%
% H = ttest2(x,y)
% H = ttest2(x,y,alpha)
% H = ttest2(x,y,alpha,tail)
% H = ttest2(x,y,alpha,tail,vartype)
% H = ttest2(x,y,alpha,tail,vartype,DIM)
% [H,PVAL] = ttest2(...)
% [h,p,ci,stats] = ttest2(...)
%
% H=1 indicates a rejection of the Null-hypothesis at a significance
% level of alpha (default alpha = 0.05).
%
% With the optional argument string TAIL, the Alternative of interest
% can be selected. If TAIL is '!=' or '<>' or 'both', the null is tested
% against the two-sided Alternative `mean (X) ~= mean (Y)'. If TAIL
% is '>' or 'right', the one-sided Alternative `mean (X) > mean (Y)' is used.
% Similarly for '<' or 'left', the one-sided Alternative `mean (X) < mean
% (Y)' is used. The default is the two-sided case.
%
% vartype support only 'equal' (default value); the value 'unequal' is not supported.
%
% H returns whether the Null-Hypotheses must be rejected.
% The p-value of the test is returned in PVAL.
%
% TTEST2 works on the first non-singleton dimension or on DIM.
%
% If no output argument is given, the p-value of the test is
% displayed.
%
%%% not supported yet
% [h,p,ci] = ttest2(...)
% [h,p,ci,stats] = ttest2(...)
% $Id$
% Copyright (C) 1995, 1996, 1997, 1998, 2000, 2002, 2005, 2006, 2007
% Kurt Hornik
% Copyright (C) 2010 by Alois Schloegl <alois.schloegl@gmail.com>
% This function is part of the NaN-toolbox
% http://pub.ist.ac.at/~schloegl/matlab/NaN/
% This program 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.
%
% This program 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 this program. If not, see <http://www.gnu.org/licenses/>.
if ((nargin < 2) || (nargin > 6) || nargout > 4)
print_usage ;
end
if (nargin < 3) || isempty(alpha)
alpha = .05;
end
if (nargin < 4) || isempty(tail)
tail = '~=';
end
if (~ ischar (tail))
error ('ttest2: tail must be a string');
end
if (nargin < 5) || isempty(vartype)
vartype = 'equal';
end
if ~strcmp(vartype,'equal')
error ('test: vartype not supported')
end
if nargin<6,
DIM = find(size(x)>1,1);
end;
if isempty(DIM), DIM=1; end;
szx = size(x);
szy = size(y);
szy(DIM) = 1;
szx(DIM) = 1;
if (any(szx-szy))
error ('ttest2: dimension of X and Y do not fit');
end
[SX, NX] = sumskipnan(x, DIM);
[SY, NY] = sumskipnan(y, DIM);
stats.df = NX + NY - 2;
MX = SX ./ NX;
MY = SY ./ NY;
if any(size(x)==0) || any(size(y)==0)
v = NaN;
else
v = sumsq(x-repmat(MX,size(x)./size(MX))) + sumsq(y-repmat(MY,size(y)./size(MY)));
end;
stats.sd = sqrt(v/stats.df);
stats.tstat = (MX - MY) .* sqrt ((NX .* NY .* stats.df) ./ (v .* (NX + NY)));
cdf = tcdf (stats.tstat, stats.df);
if (strcmp (tail, '~=') || strcmp (tail, '!=') || strcmp (tail, '<>')) || strcmp(tail,'both'),
pval = 2 * min (cdf, 1 - cdf);
elseif strcmp (tail, '>') || strcmp(tail,'right'),
pval = 1 - cdf;
elseif strcmp (tail, '<') || strcmp(tail,'left'),
pval = cdf;
else
error ('ttest2: option %s not recognized', tail);
end
h = pval < alpha;
if (nargout == 0)
fprintf(1,' pval: %g\n', pval);
end
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