3. Let X be a discrete random variablewith Pr {X = i} = ci for positive, even integers i <= 12; otherwise, the probabilityis zero, (a) Compute the value of c. (b) What is the meanof X? (c) What is the second moment of X? (d) What is the varianceof X? (e) Compute E[(X ? 5)+] where x+ is defined to be max(x,0).
Discrete random variable and Expected value.