Hsin-Fan Chen Department of Applied Economics, National Chung-Hsing University, Taiwan   250, Kuo Kuang Rd Taichung 402, Taiwan R.O.C. Taichung, Taiwan   d9034001@mail.nchu.edu.tw             JEL Areas: Q0 : Agricultural and Natural Resource Economics; Environmental and Ecological Economics: General C0 : Mathematical and Quantitative Methods: General