1. Given the same sample statistics, which level of confidence will produce the narrowest confidence interval? A) 95% B) 90% C) 85% D) 75%

2. Given the same sample statistics and level of confidence, what effect does an increase in sample size have on the width of a confidence interval? A) the width increases B) the width decreases C) there is no change

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?