Simple random |
Every individual in population has equal chance of being included in the sample Potential respondents are selected using various techniques (e.g., lottery process or random-number generator)
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Systematic random |
Starting point on a list is randomly chosen, and individuals are selected at prespecified intervals Starting point and sampling interval are determined by required sample size
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Stratified random |
Potential respondents are organized into strata or categories and sampled using simple or systematic sampling within strata to ensure possible representation of specific groups Sampled proportion can be proportionate or disproportionate across strata
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Cluster |
Population is divided into clusters that are mutually exclusive, heterogeneous and exhaustive Clusters are sampled in a stepwise manner
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