Question

For a certain random variable X it is known that E[X]=2, Var (X)=3. What is E[X*X]

Answer 1

Answer: 7

Work Shown

Var(X) = E[X^2] - ( E[X] )^2

E[X^2] = Var(X) + ( E[X] )^2

E[X^2] = 3 + 2^2

E[X^2] = 7