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, he calculated a mean a 396 and a standard deviation of 100. The 95% confidence interval results in an interval of 396 +/- 24.9793. Identify the sampling error or margin of error.