城镇居民收入的最可几分布及其基尼系数

Most Probable Distribution and the Gini Coefficient of Income of Residents in City and Town

本文研究城镇居民收入基尼系数与城镇居民资本收入占可支配收入的比例之间的数值关系。对城镇居民可支配收入分布状态提出理想化假设,从理论上导出城镇居民可支配收入的最可几分布;由城镇居民可支配收入的最可几分布导出其对应的中位数和基尼系数。研究结果表明:当城镇居民资本收入占可支配收入的比例大于0.12时,其基尼系数几乎随收入比例线性增加,收入比例每增加0.01,基尼系数约增加0.007。由最可几分布得到的中位数和基尼系数与抽样调查结果基本吻合,因为两者之差小于1%。

This paper analyzes the relation between Gini coefficient and the income proportion between capital income and disposable income. An ideal hypothesis of the disposable income of residents in city and town of China is proposed. The most probable distribution, median and Gini coefficient of the disposable income of the residents are theoretically obtained based on the hypothesis. The results show that when the income proportion between capital income and disposable income is larger than or equal to 0.12, the Gini coefficient increases linearly with the income proportion. The Gini coefficient increases approximately 0.007 for each increase of 0.01 in income proportion. Moreover, the median and Gini coefficient obtained from most probable distribution almost match with the sampling survey results because the difference between theoretical results and sampling results is less than one percent.