/usr/share/psychtoolbox-3/Quest/QuestSd.m is in psychtoolbox-3-common 3.0.9+svn2579.dfsg1-1.
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 | function sd=QuestSd(q)
% sd=QuestSd(q)
%
% Get the sd of the threshold distribution.
% If q is a vector, then the returned t is a vector of the same size.
%
% See Quest.
% Denis Pelli, 6/8/96
% 3/1/97 dgp updated to use Matlab 5 structs.
% 4/12/99 dgp dropped support for Matlab 4.
% Copyright (c) 1996-1999 Denis Pelli
if nargin~=1
error('Usage: sd=QuestSd(q)')
end
if length(q)>1
sd=zeros(size(q));
for i=1:length(q(:))
sd(i)=QuestSd(q(i));
end
return
end
p=sum(q.pdf);
sd=sqrt(sum(q.pdf.*q.x.^2)/p-(sum(q.pdf.*q.x)/p).^2);
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