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 20 incoming calls. (a) What is the expected number of calls among the 20 that involve a fax message? (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.) (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.)
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 20 incoming calls. (a) What is the expected number of calls among the 20 that involve a fax message? (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.) (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.)
Chapter8: Sequences, Series,and Probability
Section8.7: Probability
Problem 11ECP: A manufacturer has determined that a machine averages one faulty unit for every 500 it produces....
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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 20 incoming calls.
(a) What is the expected number of calls among the 20 that involve a fax message?
(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.)
(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.)
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