设D(X)=25 D(Y)=16 (rho )_(xy)=0.4,则D(X)=25 D(Y)=16 (rho )_(xy)=0.4,D(X)=25 D(Y)=16 (rho )_(xy)=0.4,D(X)=25 D(Y)=16 (rho )_(xy)=0.4,D(X)=25 D(Y)=16 (rho )_(xy)=0.4,

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