Title: Ways to get a more precise confidence interval - Minitab Express
Headings: Ways to get a more precise confidence interval
Ways to get a more precise confidence interval
Increase the sample size
Reduce variability
Use a one-sided confidence interval
Lower the confidence level

Content: Thus, you can often collect more data to obtain a more precise estimate of a population parameter. You should weigh the benefits of increased precision with the additional time and resources required to collect a larger sample. For example, a confidence interval that is narrow enough to contain only the population parameter requires that you measure every subject in the population. Obviously, such a strategy would usually be highly impractical. Reduce variability
The less that your data varies, the more precisely you can estimate a population parameter. That's because reducing the variability of your data decreases the standard deviation and, thus, the margin of error for the estimate. Although it can be difficult to reduce variability in your data, you can sometimes do so by adjusting how you collect data. For example, you can use a paired design to compare two groups. You may also be able to reduce variability by improving the process so that the process is more consistent or by measuring more precisely. Use a one-sided confidence interval
A one-sided confidence interval has a smaller margin of error than a two-sided confidence interval.