For a random variable XXX, what is the definition of Var(X)Var(X)Var(X)?
E[X2]−(E[X])2E[X^2] - (E[X])^2E[X2]−(E[X])2
E[X]−E[X2]E[X] - E[X^2]E[X]−E[X2]
E[(X−E[X])]E[(X - E[X])]E[(X−E[X])]
E[X2]E[X^2]E[X2]