[17] An investor buys 100 shares of AT&T stock and records its price change daily. [a] List several possible events for this experiment. [b] Estimate the probability for each event you described in [a]. [c] [EXTRA CREDIT ] Which concept of probability did you use in [b]? [18] The events X and Y are mutually exclusive. Suppose P(X) = 0.05 and P(Y) = 0.02. [a] What is the probability of either X or Y occurring? [b] [EXTRA CREDIT] What is the probability that neither X nor Y will happen? [19] All Seasons Plumbing has two service trucks which frequently break down. If the probability the first truck is available is 0.75; the probability the second truck is available is 0.50; the probability that both are available is 0.30. What is the probability that neither truck is available? [20] [EXTRA CREDIT] If you ask three strangers about their birthdays, what is the probability that: [a] All were born on a Wednesday? [b] All were born on different days of the week? [c] None were born