Long Test in Statistics and Probability - Estimation of Parameters
1. A study of 50 English teachers showed they spend an average of
18.4 minutes correcting a students’ composition. Find a 90%
confidence interval of the mean time when the standard deviation is
2.5 minutes. (4 points)
2. Find the sample size necessary to estimate a population mean
within 0.5 of error with 99% confidence interval and a standard
deviation of 5.3. (4 points)
For items 3 to 5, refer to this scenario: A random sample of 58 days
taken in a large hospital shows that an average of 42 patients were
admitted in the Pediatric ward per day. The standard deviation of
the population is 4. (16 points)
3. Find the 95% confidence interval of the mean number of patients
admitted in the Pediatric ward per day.
4. Find the 99% confidence interval of the mean number of patients
admitted in the Pediatric ward per day.
5. Which interval is larger? Explain why.
6. Explain the process of finding the margin of error and its
importance. (6 points)