文章研究了随机变量的相关性测度Kendall’sτ与Spearman’sρ之间的关系.利用Copula方法,得到了两者的比值ρ/τ变化的不等式.针对一类Copula参数族,证明了比值的极限值是3/2.
The relationship between Kendall's τ and Spearman's ρ is studied which are the dependence measures of random variables. The inequalities about the changes of their ratio ρ/τ are verified by using copula method. For a class of copulas with parameter , the limit of ratio is proved to be 3/2.