Mean of a distribution A random variable(r v )w takes values Wi,,, Ws with probabilities ■■■ s=1) The mean(expected value) of the distribution is the average value of the r.v., Elw]=uw= 2WSISMean of a Distribution A random variable (r.v.) w takes values w1 ,…,wS with probabilities 1 ,...,S (1 + · · · + S = 1). The mean (expected value) of the distribution is the average value of the r.v.; E[w] w w . s s s S = = =    1