Let X be a random variable. Then, E[X^2] > = E[X] . Is it always true?
Suppose that, X is a random variable, taking positive integer values, which satisfies E[(X-6)^2]=0. Then, pX(4)=pX(5). Is it always true?
Suppose that E[X] > = 0. Then, X > = 0 with probability 1, i.e., P(X >=0) =1 . Is it always true?