CRA CDs Inc. wants the mean lengths of the "cuts" on a CD to be 125 seconds (2 minutes and 5 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 eight seconds. Suppose that we select a sample of 13 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?

Shape of the distribution is

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 130 seconds? (Round the z values to 2 decimal places and the final answers to 2 decimal places.)

Percentage %

d. What percentage of the sample means will be greater than 121 seconds? (Round the z values to 2 decimal places and the final answers to 2 decimal places.)

Percentage %

e. What percentage of the sample means will be greater than 121 but less than 130 seconds? (Round the z values to 2 decimal places and the final answers to 2 decimal places.)

Percentage %