CRA CDs Inc. wants the mean lengths of the "cuts" on a CD to be 152 seconds (2 minutes and 32 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 ten seconds. Suppose that we select a sample of 20 cuts from various CDs sold by CRA CDs Inc. UseAppendix B.1for thez-values.

a.What can we say about the shape of the distribution of the sample mean?

Sample mean

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Normal

Uniform

Binomial

b.What is the standard error of the mean?(Round the final answer to 2 decimal places.)

Standard error of the meanseconds.

c.What percentage of the sample means will be greater than 156 seconds?(Round the final answer to 2 decimal places.)

Sample means%

d.What percentage of the sample means will be greater than 146 seconds?(Round the final answer to 2 decimal places.)

Sample means%

e.What percentage of the sample means will be greater than 146 but less than 156 seconds?(Round the final answer to 2 decimal places.)

Sample means%