Random variables and discrete probability distribution suppose that in order for a local high school, the school pta decides to hold a charity lottery: enter the charity lottery one grand price of $20,000 20 additional prizes of $500 tickets only $10 after reading the fine print, you discover that 10,000 tickets will be sold. therefore the probability of winning the grand prize is 1/10,000, while the probability of winning $500 is 20/10,000. is this a good bet (answered this question using the expected value also find a standard deviation). a) set up the probability model for your expected and net winning or loss of a single play. b) use ms excel to find the expected value and the standard deviation of your expected winnings.