5 14 The housing department in a large city monitors the rent for rent controlled apartments in the city The mayor wants an estimate of the average rent The housing department must deter mine the number of apartments to include in a survey in order to be able to estimate the average rent to within 100 using a 95 confidence interval From past surveys the monthly charge for rent controlled apartments ranged from 1 000 to 3 500 How many renters must be included in the survey to meet the requirements