A particular telephone number is used to receive both voice calls and fax messages. Suppose that 20% of the incoming calls involve fax messages and consider a sample of 12 incoming calls. a. What is the probability that exactly 4 of the calls involve fax messages? b. What is the probability that at most 4 of the calls involve fax messages? c. What the expected number of calls among the 12 calls that involve fax messages? d. What is the probability that the 4rd incoming call is the first fax message received?
