Cdf Plane

Suppose we have a discrete random variable X that can take on the values x = 0, 1, 2, 3 or 4. The probability mass function is given by

p_X (x)=0.2 for x=0,1,2,3 or 4. p_X (x)=0 for all other x.

-- Write down the cdf for the random variable X.
-- Sketch the cdf for the random variable X on the Cartesian-coordinate plane.
-- Find the expected value of the random variable X, that is find µX = E[X].
-- Find the variance of the random variable X, that is find σX2 = Var[X] = E[(X – µX)2].

(Note for this problem, I did not make any mention of the sample space S. This is not a problem because all we really need is the pmf for the random variable to talk about the probability it takes on values.)