3. If many 90% confidence intervals for a population mean are calculated from different samples, then what percentage of confidence intervals would you expect to NOT contain the true mean? A) 95% B) 90% C) 10% D) 5%

4. A 95% confidence interval for a mean is (18.3, 22.4). For the following, think about how such a confidence interval is calculated. This will help you figure out how to find the answer.

a) What is the margin of error associated with this interval?

b) What is the sample mean that was used to calculate this interval?