1. 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 = 19.8 and s2 = 25. 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 mean number of admissions per 24-hour period to within 1 admission with 99 percent reliability,?
2. A university dean is interested in determining the proportion of students who receive some sort of financial aid. Rather than examine the records for all students, the dean randomly selects 200 students and finds that 118 of them are receiving financial aid. Utilize a 90 percent confidence interval to estimate the true proportion of students who receive financial aid.
3. An economist is interested in studying the incomes of consumers in a particular region. The population standard deviation is called to be $1,000. A random sample of 50 individuals resulted in an average income of $15,000. What total sample size would the economist need to use for a 95 percent confidence interval if width of the interval should not be more than $100?
a) n = 1537
b) n = 385
c) n = 40
d) n = 20