Precision

Definition

Precision refers to the closeness of multiple measurements or observations to one another. It is a measure of the reproducibility or repeatability of a measurement, and it is distinct from accuracy, which is a measure of how close a measurement is to the true value.

5 Must Know Facts For Your Next Test

1. Precision is an important consideration when constructing a confidence interval for a population proportion, as it determines the width of the interval.
2. A higher level of precision, indicated by a smaller margin of error, results in a narrower confidence interval, providing more informative and useful results.
3. The level of precision required in a confidence interval depends on the intended use of the information and the acceptable level of uncertainty.
4. Factors that affect the precision of a confidence interval for a population proportion include the sample size and the desired level of confidence.
5. Increasing the sample size or the desired level of confidence can improve the precision of a confidence interval, but this may come at the cost of increased time, resources, or uncertainty.

Review Questions

• Explain how the concept of precision relates to the construction of a confidence interval for a population proportion.
  • Precision is a critical factor in the construction of a confidence interval for a population proportion. The precision of the interval is determined by the margin of error, which represents the maximum expected difference between the sample proportion and the true population proportion. A higher level of precision, indicated by a smaller margin of error, results in a narrower confidence interval, providing more informative and useful results. The level of precision required depends on the intended use of the information and the acceptable level of uncertainty, which can be influenced by factors such as the sample size and the desired level of confidence.
• Describe how the sample size and desired level of confidence can impact the precision of a confidence interval for a population proportion.
  • The sample size and desired level of confidence are two key factors that can affect the precision of a confidence interval for a population proportion. Increasing the sample size generally leads to a higher level of precision, as it reduces the standard error of the sample proportion and, in turn, the margin of error of the confidence interval. Similarly, increasing the desired level of confidence (e.g., from 90% to 95%) will result in a wider confidence interval, which can be interpreted as a decrease in precision. However, these improvements in precision may come at the cost of increased time, resources, or uncertainty, as larger sample sizes and higher confidence levels require more data collection and analysis.
• Analyze the trade-offs between precision, sample size, and confidence level when constructing a confidence interval for a population proportion.
  • When constructing a confidence interval for a population proportion, there is a trade-off between precision, sample size, and confidence level. Increasing the sample size or the desired level of confidence can improve the precision of the interval, as measured by the margin of error. However, these improvements come at a cost. Larger sample sizes require more time and resources to collect and analyze the data, while higher confidence levels result in wider intervals, which may be less informative for the intended use of the information. The optimal balance between these factors depends on the specific goals and constraints of the study, as well as the acceptable level of uncertainty. Researchers must carefully consider the trade-offs and make informed decisions to ensure that the confidence interval provides the most useful and reliable information for their needs.

Related terms

Accuracy: Accuracy is the degree to which a measurement or observation conforms to the true or accepted value.

Confidence Interval: A confidence interval is a range of values that is likely to contain an unknown population parameter, with a specified degree of confidence.

Standard Error: The standard error is a measure of the variability or dispersion of a statistic, such as the sample mean, around its true or population value.