CRA CDs Inc wants the mean lengths of the cuts on a CD to be

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 the normal distribution with a population standard deviation of 10 seconds. Suppose we select a sample of 20 cuts from various CDs sold by CRA CDs Inc.

(a) What can we say about the shape of the distribution of the sample mean? (Uniform,Binomal or Normal)

(b) What is the standard error of the mean? (Round your answer to 2 decimal places.) Standard error of the mean_____ seconds.

(c) What percent of the sample means will be greater than 154 seconds? (Round your answer to 2 decimal places. Omit the \"%\" sign in your response.) Percent _____%

(e) What percent of the sample means will be greater than 145 but less than 154 seconds? (Round your answer to 2 decimal places. Omit the \"%\" sign in your response.) Percent ____ %

Solution