同理 1 p2=p31=P42=P51=P62=6 P21=P32=P41=P52=P61=0 1 2 1/6 0 2 0 1/6 3 1/6 0 W 0 1/6 5 1/6 0 6 0 1/6 二维离散型随机变量(X,)的分布函数为F(x,y)=∑P, x≤x y≤y同理 , 6 1 p22 = p31 = p42 = p51 = p62 = 0 p21 = p32 = p41 = p52 = p61 = Y X 1 2 1 1 / 6 0 2 0 1 / 6 3 1 / 6 0 4 0 1 / 6 5 1 / 6 0 6 0 1 / 6 二维离散型随机变量(X，Y)的分布函数为  .   = y y x x ij j i F(x, y) p