Sampling Methods Math Example 3
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Example 3
easyA researcher wants to study opinions of 10,000 employees across 50 departments. She randomly selects 5 departments and surveys all employees in those departments. What sampling method is this, and what are its limitations?
Solution
- 1 Method: cluster sampling — departments are the clusters; randomly selected clusters are fully surveyed
- 2 Limitation 1: departments may be internally homogeneous (employees in the same department may share similar views)
- 3 Limitation 2: only 5 of 50 departments are represented — departments not selected have zero chance of inclusion
- 4 Limitation 3: less statistically efficient than SRS for the same total sample size
Answer
Cluster sampling. Limitation: departments may be homogeneous; non-selected departments have no representation.
Cluster sampling is efficient when subjects are naturally grouped and groups are expensive to travel between. The key limitation is that within-cluster homogeneity reduces the effective information gained — 50 employees from one department provide less diversity than 50 employees from 50 different departments.
About Sampling Methods
Systematic approaches for selecting a subset of individuals from a population. The main probability methods are: simple random sample (SRS), stratified random sample, cluster sample, and systematic sample. Convenience sampling is a non-probability method that is generally biased.
Learn more about Sampling Methods →More Sampling Methods Examples
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