IBE, University of Munich, Technische Fachhochschule Berlin and Department of Statistics, University of Munich, Germany. hummel@ibe.med.uni-muenchen.de|IBE, University of Munich, Technische Fachhochschule Berlin and Department of Statistics, University of Munich, Germany. hummel@ibe.med.uni-muenchen.de|IBE, University of Munich, Technische Fachhochschule Berlin and Department of Statistics, University of Munich, Germany. hummel@ibe.med.uni-muenchen.de