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, the mean is 19.8 and the sample variance = 25. Find the upper limit of a 95% confidence interval for the mean number of admissions per 24-hour period.