Stat 226 - Chapter 13

02/16/14

Announcements

  • Exam 1 is this Thursday. Same time and place as lecture.
  • Sample exams, study guide, cover sheet, etc. are available on Blackboard.
  • On Thursday, hand in the homework after the exam and leave quietly.
  • Bring a calculator and a pencil (everything else should be in your backpack).
  • I take cheating very seriously.

Outline of Chapter 13

  • GOAL: Estimate an unknown value via sampling
  • The unknown value usually refers to the population parameter (\( \mu \))
  • In order to estimate \( \mu \), we commonly sample (or take a subset) from the population of interest. Certain sampling methods can introduce bias. We want an unbiased estimate of \( \mu \).
  • Lots of different ways to sample, some are better than others. We cover five different methods.

Survey

Sampling Schemes

  • Simple Random Sample (most common - typically no bias)
  • Stratified Random Sample (less common - typically no bias)
  • Cluster Sampling (common in geographic studies - typically no bias)
  • Voluntary Response (quite common - quite terrible - usually biased)
  • Convenience Sampling (quite common - quite terrible - usually biased)