问题如下图:
选项:
A.
B.
C.
解释:请问这个问的是什么?哪一节讲的?
NO.PZ2017092702000086问题如下The totnumber of parameters thfully characterizes a multivariate normstribution for the returns on two stocks is:A.3.B.4.C.5. C is correct.A bivariate normstribution (two stocks) will have two means, two variances anone correlation. A multivariate normstribution for the returns on n stocks will have n means, n variances ann(n – 1)/2 stincorrelations.这道题目问衡量两只同时服从正态分布的的股票,需要几个参数。可以从如下的角度出发分析一个正态分布有两个参数,均值和方差。所以从两只股票各自都服从正态分布的角度出发,就各自有一个均值和一个方差,一共是四个参数。从两只股票还要同时都服从正态分布的角度出发,还需要有一个correlation的参数,一共就是5个。 算上协方差,会是6种参数,为啥不用协方差
NO.PZ2017092702000086 为什么还要考虑correlations?
NO.PZ2017092702000086 4. 5. C is correct. A bivariate normstribution (two stocks) will have two means, two variances anone correlation. A multivariate normstribution for the returns on n stocks will have n means, n variances ann(n – 1)/2 stincorrelations.所以真的是一脸懵逼,所以对于这种问题怎么解决呢
这道题不是很懂,请帮忙讲解下。谢谢。
讲义里没有,但原版书有,那我还看不看原版书?