Learning Objectives

  • Explain the problems with point estimates and the need for confidence intervals.
  • Explain the trade-off between confidence and precision.
  • Identify the key elements of the t curve, and use sample size to select the correct distribution (z or t).
  • Use a specified confidence level to find alpha and the critical value of z or t.
  • Identify the correct distribution and formula for a given sample statistic and sample size.
  • Calculate and interpret confidence intervals for means and proportions with different confidence levels and sample sizes.