The mean (or expected value) of a probability distribution can be calculated by first making the probability distribution. Then multiply the possible values of the Random Variable by their probabilities (X*P(X)) then add all the X*P(X) up. On the TI 83/84 calculator you can 1) Enter the values of the RV's into List 1 (Press STAT, 1 (for Edit), highlightt L1 and press CLEAR if needed, then enter values into the list) 2) Enter the probabilities into L2 (press > and then enter the values in the list. highlight L2 and press CLEAR first if needed). 3) 2nd MODE (to quit the list) 4) STAT, > (for CALC), select 1-Var Stats, List: L1 (2nd 1), FreqList: L2 (2nd 2). Then calculate. x is the expected value (mean) of the frequency distribution. Find the mean: X P(X) 5 0.3 3 0.5 -2 0.2