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  2. Stratified sampling - Wikipedia

    en.wikipedia.org/wiki/Stratified_sampling

    In statistics, stratified sampling is a method of sampling from a population which can be partitioned into subpopulations. Stratified sampling example In statistical surveys , when subpopulations within an overall population vary, it could be advantageous to sample each subpopulation ( stratum ) independently.

  3. Stratified randomization - Wikipedia

    en.wikipedia.org/wiki/Stratified_randomization

    Graphic breakdown of stratified 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 ...

  4. Stratification (clinical trials) - Wikipedia

    en.wikipedia.org/wiki/Stratification_(clinical...

    Proportionate stratified sampling involves selecting participants from each stratum in proportions that match the general population. [1] This method can be used to improve the sample's representation of the population, by ensuring that characteristics (and their proportions) of the study sample reflect the characteristics of the population.

  5. Design effect - Wikipedia

    en.wikipedia.org/wiki/Design_effect

    Different sampling designs and statistical adjustments may have substantially different impact on the bias and variance of estimators (such as the mean). [citation needed] An example of a design which can lead to estimation efficiency, compared to simple random sampling, is Stratified sampling. This efficiency is gained by leveraging ...

  6. Variance reduction - Wikipedia

    en.wikipedia.org/wiki/Variance_reduction

    importance sampling; stratified sampling; moment matching; conditional Monte Carlo; and quasi random variables (in Quasi-Monte Carlo method) For simulation with black-box models subset simulation and line sampling can also be used. Under these headings are a variety of specialized techniques; for example, particle transport simulations make ...

  7. Sampling (statistics) - Wikipedia

    en.wikipedia.org/wiki/Sampling_(statistics)

    In statistics, quality assurance, and survey methodology, sampling is the selection of a subset or a statistical sample (termed sample for short) of individuals from within a statistical population to estimate characteristics of the whole population. The subset is meant to reflect the whole population, and statisticians attempt to collect ...

  8. Multistage sampling - Wikipedia

    en.wikipedia.org/wiki/Multistage_sampling

    In statistics, multistage sampling is the taking of samples in stages using smaller and smaller sampling units at each stage. [1] Multistage sampling can be a complex form of cluster sampling because it is a type of sampling which involves dividing the population into groups (or clusters). Then, one or more clusters are chosen at random and ...

  9. Sample size determination - Wikipedia

    en.wikipedia.org/wiki/Sample_size_determination

    In practice, the sample size used in a study is usually determined based on the cost, time, or convenience of collecting the data, and the need for it to offer sufficient statistical power. In complex studies, different sample sizes may be allocated, such as in stratified surveys or experimental designs with multiple treatment groups.