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: Ways to get a more precise confidence interval - Minitab Express
Ways to get a more precise confidence interval
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If your confidence interval is too wide, you cannot be very certain about the true value of a parameter, such as the mean. However, you can use several strategies to reduce the width of a confidence interval and make your estimate more precise. The characteristics that follow affect the width of the confidence interval. Sample size
Variation in the data
Type of interval
Confidence level
Increase the sample size
Often, the most practical way to decrease the margin of error is to increase the sample size. Usually, the more observations that you have, the narrower the interval around the sample statistic is. 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.