Stratification
12 definitions

Stratification

Means of improving the quality of a probability sample by selecting sample elements according to population variables with known distribution profiles in order to determine a proportional or disproportional allocation of the survey sample. Examples of commonly used stratification variables are "region", "type of settlement" and "household size".

Stratification

Stratification involves dividing the sampling frames into subsets (called strata) prior to the selection of a sample for statistical efficiency, for production of estimates by stratum, or for operational convenience. Stratification is done such that each stratum contains units that are relatively homogeneous with respect to variables that are believed to be highly correlated with the information requested in the survey

Stratification

Stratification means the process of dividing a population into sub-populations, each of which is a group of sampling units which have similar characteristics (often monetary value).

Stratification

Thermal layering of water in lakes and streams. Lakes usually have three zones of varying temperature, the epilimnion, the metalimnion, and the hypolimnion. The formation of separate layers (of temperature, plant, or animal life) in a lake or reservoir.

Stratification

The process or result of separating a sample into sub-samples according to specified criteria, such as age or occupational group.

Stratification

The separation of the water column into layers, with the densest at the bottom and the lease dense at the surface, typically caused by temperature and/or salinity. A stratified water column is said to be stable.

Stratification

Stratification consists of dividing the population into subsets (called strata) within each of which an independent sample is selected.

Stratification

The formation of distinct layers with different temperatures, salinity, or oxygen content in the ocean or another body of water. When the water column becomes stratified with a layer of warm, buoyant water at the surface and a layer of colder, denser water below, vertical mixing (upwelling) slows down or stops. The lack of mixing can cause deeper water to become oxygen depleted, while surface waters become nutrient depleted.

Stratification

The division of a population into parts, or strata, each of which is more homogeneous than the population as a whole. If sample sizes for these strata are set proportional to the stratum share of the population, then the resultant sample will be more efficient than a simple random sample of the population disregarding the strata, as the simple random sample will have resultant sample sizes for each stratum that are randomly smaller or larger than the stratum share (too much in one stratum, too little in others, by chance).

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About this term

Stratification has been defined 12 different ways in documents like Television Audience Measurement, Information Quality Glossary, FRTR Glossary, and 7 more.

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