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幼苗
共回答了13个问题采纳率：76.9% 举报
E(X)=E(Y)=0,D(X)=D(Y)=4,E(X^2)=D(X)+[E(x)]^2=D(X)=4,E(Y^2)=4;
E(U)=3E(X)+2E(Y)=0,E(V)=3E(X)-2E(Y)=0;D(U)=D(V)=9D(X)+4D(Y)=52;
E(UV)=E(9X^2-4Y^2)=9E(X^2)-4E(Y^2)=20;
COV(U,V)=E(UV)-E(U)E(V)=20;
p=COV(U,V)/√[D(U)D(V)]=20/52=5/13.
1年前
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