1. Business and Economic Statistics: Stratified and Clustered Sampling
Presenter: Sam Capurso

2. 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

3. Use this as...
A refresher Or
To resolve any knowledge gaps you have

4. Different characteristics
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

5. 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

6. 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

7. 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 ?

8. Why conducted Clustered Sampling?
Reduce costs
Convenience (not convenience sampling!)
Practicality $

9. Stratified Sampling (SS) Clustered Sampling (CS)
Summary
Stratified Sampling (SS)
Clustered Sampling (CS)
Groups same within: homogenous
Groups have no defining characteristic – are representative of population: heterogeneous
Groups are different from each other
Groups are roughly the same as each other
SRS taken from each group
Census taken from each group
Know examples of strata
Know examples of clusters
Know reasons for conducting Stratified Sampling
Know reasons for conducting Clustered Sampling
End

10. 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

11. Terminology_slide 4 (for assessor only)
Stratum & strata
Clustered
Sampling
Census
Population
Simple Random
Sample (SRS)
Stratified
Sampling
New terms in bold