− | 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.<ref name=":3" /><ref>{{Citation|title=Simple random sample|date=2020-03-18|url=https://en.wikipedia.org/w/index.php?title=Simple_random_sample&oldid=946144051|work=Wikipedia|language=en|access-date=2020-04-07}}</ref> 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.<ref>{{Citation|title=Stratified sampling|date=2020-02-09|url=https://en.wikipedia.org/w/index.php?title=Stratified_sampling&oldid=939938944|work=Wikipedia|language=en|access-date=2020-04-07}}</ref> This sampling method should be distinguished from [[cluster sampling]], where a simple random sample of several entire clusters is selected to represent the whole population, or stratified systematic sampling, where a [[systematic sampling]] is carried out after the stratification process. Stratified random sampling is sometimes also known as "'''quota random sampling'''".<ref name=":3">{{Cite web|url=https://www.investopedia.com/ask/answers/032615/what-are-some-examples-stratified-random-sampling.asp|title=How Stratified Random Sampling Works|last=Nickolas|first=Steven|date=July 14, 2019|website=Investopedia|language=en|access-date=2020-04-07}}</ref>
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| In statistics, stratified randomization is a method of sampling which first stratifies the whole study population into subgroups with same attributes or characteristics, known as strata, then followed by simple random sampling from the stratified groups, where each element within the same subgroup are selected 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 population, or stratified systematic sampling, where a systematic sampling is carried out after the stratification process. Stratified random sampling is sometimes also known as "quota random sampling". | | In statistics, stratified randomization is a method of sampling which first stratifies the whole study population into subgroups with same attributes or characteristics, known as strata, then followed by simple random sampling from the stratified groups, where each element within the same subgroup are selected 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 population, or stratified systematic sampling, where a systematic sampling is carried out after the stratification process. Stratified random sampling is sometimes also known as "quota random sampling". |