(1)P(X=iY=0)= P(X=i,Y=0) P(Y=0 P(X=i, Y=0) i=0.1.2.3 8/27 将表中第一行数据代入得条件分布 123 P(X=iY=0)1/83/83/818X P(X = i Y = 0) 0 1 2 3 1/8 3/8 3/8 1/8 将表中第一行数据代入得条件分布 ( 0) ( , 0) ( 0) = = = = = = P Y P X i Y P X i Y 8/ 27 ( = , = 0) = P X i Y i = 0,1,2,3 (1)