填空题
23.设随机变量X1，X2，X3相互独立，且X1～B
- 1、
【正确答案】
1、
【答案解析】E[X1(X1+X2-X3)]=E(
+X1X2-X1X3)
=E(
)+EX1EX2-EX1EX3
=DX1+(EX1)2+EX1EX2-EX1EX3
=
+X1X2-X1X3)=E(
)+EX1EX2-EX1EX3=DX1+(EX1)2+EX1EX2-EX1EX3
=