The records of the 100 postal employees at a postal station in a large city showed that the average time these employees had worked for the postal service was 9.2 years and the standard deviation s = 5.1 years. A 95% confidence interval for the mean time the population of U.S. postal service employees have spent with the postal service is
	9.2 1.05. 1.01 9.2. 9.2 9.80. not trustworthy.