An Advisor to the Mayor of a Large City Wants

Short Answer

An advisor to the mayor of a large city wants to estimate,within 2.450 minutes,the mean travel time to work for all employees who work within the city limits.He knows that the standard deviation of all travel times is 11.35 minutes.He also wants to achieve a 95% confidence interval.He will poll a random sample of city employees.How many employees should he poll?