d(aξ+b)=a2dξD（aξ+b）=a2Dξ

d(aξ+b)=a2dξD（aξ+b）=a2Dξ 怎么证的?

1个回答

D(aξ+b）=(a^2)Dξ 怎么证的?
证:D(aξ+b）= E{[(aξ+b-(E(aξ)+b)]^2}
=E{[(aξ+b-a(Eξ)-b)]^2}
=E{[aξ-a(Eξ)]^2}
=(a^2)Dξ