The proportion of American Express credit-card holders who pay their credit card bill in full each month is 23%; the other 77% make only a partial or no payment.
(a) In a random sample of 15 customers, what is the probability that:
i. 4 customers pay their bill in full?
ii. More than 6 customers pay their bill in full?
(b) In a random sample of 17 customers, what is the probability that:
i. 4 customers pay their bill in full?
ii. No more than 3 customers pay their bill in full?