Question

数学期望的公式

Answer 1

E=x1p1 x2p2 x3p3 ... xn*pn

Answer 2

E=x1p1+x2p2+x3p3+...+xnpn

Answer 3

DX=E(X^2-2XEX+(EX)^2) =E(X^2)-E(2XEX)+(EX)^2 =E(X^2)-2(EX)^2+(EX)^2 =E(X^2)-(EX)^2

Answer 4

Answer 5

E=x1*p1+x2*p2+...+xn*pn