NO.PZ2015120604000064
问题如下:
According to the above table, what is the correlation of X and Y, given the joint probability table above?
选项:
A. -0.98.
B. 0.16.
C. 0.98.
解释:
A is correct
,
Cov(X,Y)=-4.8, standard deviations of X and Y are 1.90 and 2.58, as calculated before,
thus correlation of X and Y is -0.98
Nan🌞 · 刚刚 请问一下表格里的第一个概率0.2,为什么既可以作为X=-2的概率,又可以作为(X-E(X))^2的概率,还可以作为X和Y的联合概率呢?