Affiliation: | 1. Department of Applied Statistics , National Taichung Institute of Technology , 129, Sec. 3, San-min Rd., Taichung City, Taichung 404, Taiwan yhchien@ntit.edu.tw;3. Department of Business Administration , Kao-Yuan University , 1821, Chung-Shan Rd., Lu-Chu Hsiang, Kaohsiung County 821, Taiwan |