Guest User

Untitled

a guest
May 22nd, 2018
71
0
Never
Not a member of Pastebin yet? Sign Up, it unlocks many cool features!
text 0.16 KB | None | 0 0
  1. f(x)=E[(X-x)^2]
  2. =E[X^2-2Xx+x^2]
  3. =E[X^2]-2xE[X]+x^2
  4. =E[X^2]-2xμ+x^2
  5. f(x) is minimum where f'(x)=0
  6. =>f'(x)=-2μ+2x=2(x-μ)=0
  7. =>x=μ
  8. =>f(x)=E[X^2]-μ^2=Var(X)
Add Comment
Please, Sign In to add comment