1.已知二维随机变量X和Y的联合分布律为-|||-Y/X 1 2 3-|||--1 0.2 0.1 0-|||-0 0.1 0 0.3-|||-1 0.1 0.1 0.1-|||-则E(X)= E(Y)= E(XY)=D(X )=-|||-D(Y)= Cov(X,Y)= rho xY=