Confidence Intervals

By the end of this module, learners should be able to:

  • Describe the purpose and interpretation of confidence intervals for proportions and means,
  • Identify the quantities that are random and not random in the construction of confidence intervals,
  • Apply the large sample sampling distribution of a sample proportion to calculate confidence intervals for proportions,
  • Determine the sample size necessary for a confidence interval for a proportion to be sufficiently narrow,
  • Describe the t-distribution and explain when it should be used and how it differs from a Normal distribution,
  • Apply the sampling distribution of the sample mean to calculate confidence intervals,
  • State the meaning of robust when used to describe coverage of a confidence interval, recall the role of sample size in the robustness of a confidence interval, and recognize situations when confidence intervals for means and for proportions are not robust.

Topics covered in this module

Expected time to complete the learning resources in this module: 2 hours.

Learning resources:

  1. Data Used in this Module
  2. Introduction to Confidence Intervals (video)
  3. Confidence Intervals for Proportions (video)
  4. Sample Size for Estimating a Proportion (video)
  5. Confidence Intervals for Means (video)
  6. Robustness of Confidence Intervals (video)
  7. Guide to carrying out the analysis in this module using R (pdf)
  8. Guide to carrying out the analysis in this module using SPSS (pdf)