1. School of Statistics and Center of Statistical Research, Southwestern University of Finance and Economics, Chengdu, China
2. School of Economics, Xiamen University, Fujian, China
3. Center of Statistical Research, Southwestern University of Finance and Economics, Chengdu, China
4. Guanghua School of Management, Peking University, Beijing, China
5. School of Economics and The Wang Yanan Institute for Studies in Economics, Xiamen University, Fujian, China