suppose an airline sells 300 tickets when there is only 270 seats available. on avg, 15% of those with tickets do not show up. what is the probability that there will be enough seats for everybody who shows up?
A special roulette wheel has seven equally likely outcomes: 0, 1, 2, 3, 4, 5, 6. If you bet that an odd number comes up, you win or lose $10 according to whether or not that event occurs. If X denotes your ‘net’ gain, X=10 if we see 1, 3, or 5, and X = -10 otherwise. Suppose that you play this game 400 times. Let Y be your net gain after these 400 plays. The mean (expectation) and standard deviation of Y are...
i'd figured out the mean (its -571) but how do u figure out the stnd dev?