Response to the following question: Shape of the distribution of the Sample Mean
CRA CDs, Inc. wants the mean lengths of the "cuts" on a CD to be 135 seconds (2 minutes and 15 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 the normal distribution with a standard deviation of 8 seconds. Suppose we select a sample of 16 cuts from various CDs sold by CRA CDs, Inc. What can we say about the shape of the distribution of the sample mean?
A. 67% of the sample means will be between 127 seconds and 143 seconds.
B. 95% of the sample means will be between 127 seconds and 143 seconds.
C. 99% of the sample means will be between 127 seconds and 143 seconds.
D. 100% of the sample means will be between 127 seconds and 143 seconds.
Part c, d, e) Use Excel's NORMDIST function.