利用條件評估法 (contingent valuation method) 來評估非市場財貨之市場隱含價值時，雙界二分選擇法 (doubled-bound dichotomous choice method) 為最普遍的詢價方式。近年來，藉由此詢價方式來估計受訪者心目中的願付價值 (willingness to pay) 之研究中，更將此方法推廣至同時估計兩個以上且具有相關性的非市場財貨。只是文獻中的相關探討多半忽略其間的相關性，此外所採用的模型也有可能導致估計的願付價值會有小於零的情形產生。因此，本文引進了衍生版本的Bivariate Generalized Gamma Distribution，來解決這上述兩個問題。我們並採用「竹東及朴子地區心臟血管疾病之危險因子長期追□研究」中，第五循環的「肥胖之願付價格問卷」來作實證分析。在其餘的條件不變的情況下，分析結果顯示，居住在竹東、女性、教育程度愈高、年紀愈小、體重愈重及收入愈高的受訪者會願意支付較高的金額來接受減肥的療程；此外，認為肥胖會影響工作及社交關係的受訪者也會願意支付較高的金額。 / In a contingent valuation survey, it is quite often that subjects were asked to respond to more than one WTP (willingness-to-pay) scenarios. Under such a circumstance, responses provided by a subject are clearly correlated. Although the issue is well recognized in the past, in practice a popular strategy in analyzing this sort of data, however, simply ignore the issue and treat them as if they were totally uncorrelated. Concerning that WTP prices can take only non-negative values along with the issue of possible correlation, we propose an “extend bivariate generalized gamma distribution” that can be used to deal with data collected under a two-scenario situation. Applying it to the CVDFACTS study, where subjects were asked to evaluate a medication-only program as well as a medication-and-exercise program, we found that, other things being equal, female subjects, subjects residing in Chu-Dung County, subjects weigh more, subjects with younger age, higher income, and more years of schooling are willing to pay more. In addition, those who think obesity would affect their social activities would also have higher WTP prices.