NO.PZ2018062016000086
问题如下:
An analyst uses a multivariate normal distribution to precisely model the returns on 3 stocks, how many parameters should he get at the beginning?
选项:
A. 6
B. 8
C. 9
解释:
C is correct. Based on relevant concept, to calculate the returns on n stocks, a multivariate normal distribution will have n means, n variances and n(n – 1)/2 distinct correlations.
In this case, 3 stocks will have 3 means, 3 variances and 3 correlation, the sum is 9.
为什么需要corelation?