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二维随机函数协方差 已知二维随机向量 (X,Y)的密度函数f(x,y)=13(x+y),求协方差C...
二维离散型随机变量方差怎样算 E(X)=∑xP(x,y)=1*0.1+1*0.3+2*0.4+2*0.2=1.6D(X)=E[(X-EX)^2]=∑(x-EX)^2 P(x,y)=(1-1.6)^2*0.1+(1-1.6)^2*0.3+(2...
二维离散型随机变量方差怎样算 E(X)=∑xP(x,y)=1*0.1+1*0.3+2*0.4+2*0.2=1.6D(X)=E[(X-EX)^2]=∑(x-EX)^2 P(x,y)=(1-1.6)^2*0.1+(1-1.6)^2*0.3+(2...