The Security Department of a State University Is Planning Its

Multiple Choice

The security department of a state university is planning its budget for the next year.In estimating the man-hours for security during university sponsored music concerts,the average length of music concerts is needed.A random sample from thirty-six security departments at universities was taken and the sample mean length of concerts was 160 minutes.Suppose the population standard deviation is 45 minutes.A 95 percent confidence interval for the true mean duration of music concerts is:

A) 157.55 to 162.45.
B) 147.63 to 172.37.
C) 71.8 to 248.2.
D) 145.3 to 174.7.
E) 1601.96(45 / 36) .