[1] Chinese Univ Hong Kong, Dept Stat, Hong Kong, Peoples R China
[2] Univ Oxford, Dept Stat, Oxford OX1 1NF, England
[3] Univ Oxford, Nuffield Coll, Oxford, England
[4] Chinese Univ Hong Kong, Dept Econ, Hong Kong, Peoples R China
[5] Chinese Univ Hong Kong, Dept Econ, Shatin, 903 Esther Lee Bldg, Hong Kong, Peoples R China