--- /dev/null
+function Q=iqr(Y,DIM)
+% IQR calculates the interquartile range
+% Missing values (encoded as NaN) are ignored.
+%
+% Q = iqr(Y)
+% Q = iqr(Y,DIM)
+% returns the IQR along dimension DIM of sample array Y.
+%
+% Q = iqr(HIS)
+% returns the IQR from the histogram HIS.
+% HIS must be a HISTOGRAM struct as defined in HISTO2 or HISTO3.
+%
+% see also: MAD, RANGE, HISTO2, HISTO3, PERCENTILE, QUANTILE
+
+
+% $Id$
+% Copyright (C) 2009 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,
+ DIM = [];
+end;
+if isempty(DIM),
+ DIM = min(find(size(Y)>1));
+ if isempty(DIM), DIM = 1; end;
+end;
+
+
+if nargin<1,
+ help iqr
+
+else
+ Q = quantile(Y,[1,3]/4,DIM);
+ Q = diff(Q,[],DIM);
+end;
+
+
+