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Business and Economic Statistics : Stratified and Clustered Sampling. Presenter: Sam Capurso. Objectives. Be able to explain and apply the following concepts: Stratified Sampling Clustered Sampling Give examples of strata and clusters
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Business and Economic Statistics:Stratified and Clustered Sampling Presenter: Sam Capurso
Objectives • Be able to explain and apply the • following concepts: • Stratified Sampling • Clustered Sampling • Give examples of strata and clusters • Explain why you would use Stratified Sampling and Clustered Sampling
Use this as... • A refresher • Or • To resolve any knowledge gaps you have
Stratified Sampling • Split the population into groups (strata) whereby: • Each stratum is the same within • Each stratum is different between • Take a SRS from each stratum • Be careful! You can’t have more than one of the same strata Strata Different characteristics
Clustered Sampling • Select or construct groups (clusters) whereby: • Each cluster is roughly the same as the others • The clusters are representative of the entire population • Randomly select clusters and then take a census of these • Be careful! CS is not SRS! Clusters Random Selection
Application • What are some examples of strata? • What are some examples of clusters? • Scenario: You want to survey nurses in Australian hospitals to ask their attitudes towards their work conditions and pay
Why conducted Stratified Sampling? • You have reason to believe that people of a similar characteristic will respond in a particular way • You want to reduce variability in the samples • You want to reflect proportions of groups in the population ?
Why conducted Clustered Sampling? • Reduce costs • Convenience (not convenience sampling!) • Practicality $
Summary End
Please note_(this was shown before the presentation) • As you know, I am currently undertaking a Certificate IV in Training and Assessment at TAFE SA • This presentation is being recorded, and will be submitted for assessment
Terminology_slide 4 (for assessor only) • Stratum & strata • Clustered • Sampling • Census • Population • Simple Random • Sample (SRS) • Stratified • Sampling New terms in bold