Question

已知X~N(-2,0.16).求E(X+3)的平方.

Answer 1

E(X)=-2 VarX=EX^2-(EX)^2=EX^2-4=0.16

所以EX^2=4.16

E(X+3)^2=E(X^2+6X+9)=E(X^2)+6EX+9=4.16-12+9=1.16