题目

若 X,Y 独立,则()A. D(X-3Y)=DX-9DYB. D(XY)=DXcdot DYC. E[(X-EX)(Y-EY)]=0D. PY=aX+b=1

若 $X,Y$ 独立,则()

A. $D(X-3Y)=DX-9DY$

B. $D(XY)=DX\cdot DY$

C. $E[(X-EX)(Y-EY)]=0$

D. $P\{Y=aX+b\}=1$

题目解答

答案

C. $E[(X-EX)(Y-EY)]=0$