CRA CDs Inc. wants the mean lengths of the “cuts” on a CD to be 128...

CRA CDs Inc. wants the mean lengths of the “cuts” on a CD to be 128 seconds (2 minutes and 8 seconds). This will allow the disk jockeys to have plenty of time for commercials within each 10-minute segment. Assume the distribution of the length of the cuts follows a normal distribution with a standard deviation of nine seconds. Suppose that we select a sample of 18 cuts from various CDs sold by CRA CDs Inc. Use Appendix B.1 for the z-values. a. What can we say about the shape of the distribution of the sample mean? Sample mean b. What is the standard error of the mean? (Round the final answer to 2 decimal places.) Standard error of the mean seconds. c. What percentage of the sample means will be greater than 134 seconds? (Round the final answer to 2 decimal places.) Sample means % d. What percentage of the sample means will be greater than 124 seconds? (Round the final answer to 2 decimal places.) Sample means % e. What percentage of the sample means will be greater than 124 but less than 134 seconds? (Round the final answer to 2 decimal places.) Sample means %

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(a) and (b)

(c)

(d) and (e)

orchestra answered 1 year ago

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