设二维随机变量(X,Y)的分布列为如下表,

Question

设二维随机变量(X,Y)的分布列为如下表,

Answer 1

X的边缘分布：p(X=0)=P(X=0,Y=-1)+P(X=0,Y=0)=1/3+1/4=7/12
                        p(X=1)=P(X=1,Y=-1)+P(X=1,Y=0)=1/4+1/6=5/12
  2  
y的边缘分布：p(Y=-1)=P(X=0,Y=-1)+P(X=1,Y=-1)=1/3+1/4=7/12
                       p(Y=0)=P(X=0,Y=0)+P(X=1,Y=0)=1/4+1/6=5/12


3   P(X=0,Y=-1)不等于p(X=0)p(Y=-1) 从而不独立