1. In general, when we construct a confidence interval, we want to obtain as precise of an estimate as possible of the unknown population parameter. Look carefully at the following five combinations of sample size and confidence level that the academic adviser could have used to obtain her estimate. Which combination would lead to the most precise estimate?

1. n = 200, confidence level = 95%
2. n = 645, confidence level = 90%
3. n = 645, confidence level = 99%
4. n = 1800, confidence level = 90%
5. n = 1800, confidence level = 99%