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2#
发表于 2011-7-13 16:50
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Simple Random - Every object has equal chance of being selected from a population
Cluster - "Break" population into group (cluster) and randomly sample n groups. (Mostly use when geographic coverage is huge because the cost of traveling to all group is high).
Stratified - Classify population according to certain characteristics (e.g. Gender, Age etc). Next, randomly select objects from each classification. Group all the objects into a final sample. |
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