1. a Department of Statistics , Pontificia Universidad Católica de Chile, Chile, and Measurement Center MIDE UC, Pontificia Universidad Católica de Chile , Chile
2. b Department of Statistics , Pontificia Universidad Católica de Chile , Chile
3. c L-BioStat , , Katholieke Universiteit Leuven, Belgium, and Department of Biostatistics, Erasmus Medical Center , Rotterdam , The Netherlands