stratified random sample

views updated May 14 2018

stratified random sample (partial random sample) In statistics, a modification of the random sample that is particularly useful when obvious heterogeneity exists in the community, area, etc. to be investigated. In such instances a simple random sample may fail to record sufficient replicates of a particular subcategory, or may do so only very inefficiently, so preventing a proper statistical monitoring of variability. In a stratified random scheme sample points are shared among the main types present, then allocated at random within those subcategories.

stratified random sample

views updated May 18 2018

stratified random sample(partial random sample) In statistics, a modification of the random sample that is particularly useful when obvious heterogeneity exists in the community, area, etc. to be investigated. In such instances a simple random sample may fail to record sufficient replicates of a particular subcategory, or may do so only very inefficiently, so preventing a proper statistical monitoring of variability. In a stratified random scheme sample points are shared among the main types present, then allocated at random within those subcategories.

stratified random sample

views updated Jun 08 2018

stratified random sample (partial random sample) In statistics, a modification of the random sample that is particularly useful when obvious heterogeneity exists in the community, area, etc. to be investigated. In such instances a simple random sample may fail to record sufficient replicates of a particular subcategory, or may do so only very inefficiently, so preventing a proper statistical monitoring of variability. In a stratified random scheme sample data points are divided into classes (strata) before taking a random sample within each stratum.

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