A particular telephone number is used to receive both voice calls and fax messages. Suppose that 25% of the incoming calls involve fax messages, and consider a sample of 20 incoming calls.

(a) What is the expected number of calls among the 20 that involve a fax message? E(X)-5

(b) What is the standard deviation of the number among the 20 calls that involve a fax message? (Round your answer to three decimal places.) Ox= 1.936

(c) What is the probability that the number of calls among the 20 that involve a fax transmission exceeds the expected number by more than 2 standard deviations? (Round your answer to three decimal places.)