Difference between Strata and Clusters
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Strata |
Clusters |
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a. All strata are represented in the sample. |
a. Only a subset of clusters is in the sample. |
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b. Best results occur when elements within strata are internally homogenous. |
b. Best results occurs with clusters, when clusters are internally heterogenous. |
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c. Population divided into few subgroups. |
c. Population divided into many subgroups. |
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d. Choice of elements is within subgroups. |
d. Random choice of sub groups. |