As an aid to the establishment of personnel requirements, the director of a hospital wishes to estimate the mean number of people who are admitted to the emergency room during a 24-hour period. the director randomly selects 64 different 24-hour periods and determines the number of admissions for each. for this sample, x = 396 and s = 100. using the sample standard deviation as an estimate for the population standard deviation, what size sample should the director choose if she wishes to estimate the