X and Y are discrete random variables, with possible values x1; x2; x3 and y1; y2; y3
respectively. Denote pij the joint probability of xi and yj ; where i, j ?{1, 2, 3}.
(For example, the probability P( { X = x1} ? {Y = y3}) is denoted by p13.) De fine
a discrete random variable U = X + 2Y: Show that E = E[X] + 2E[Y ].
respectively. Denote pij the joint probability of xi and yj ; where i, j ?{1, 2, 3}.
(For example, the probability P( { X = x1} ? {Y = y3}) is denoted by p13.) De fine
a discrete random variable U = X + 2Y: Show that E = E[X] + 2E[Y ].