Stratified Randomization
In statistics, stratified randomization is a method of Sampling (statistics), sampling which first stratifies the whole study Statistical population, population into Statistical population, subgroups with same Variable and attribute (research), attributes or characteristics, known as strata, then followed by Simple random sample, simple random sampling from the stratified groups, where each element within the same subgroup are selected Bias (statistics), unbiasedly during any stage of the sampling process, randomly and entirely by chance. Stratified randomization is considered a subdivision of stratified sampling, and should be adopted when shared attributes exist partially and vary widely between subgroups of the investigated population, so that they require special considerations or clear distinctions during sampling. This sampling method should be distinguished from cluster sampling, where a simple random sample of several entire clusters is selected to represent the whole popula ...
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