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  2. 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 ...

  3. Stratified sampling - Wikipedia

    en.wikipedia.org/wiki/Stratified_sampling

    Proportionate allocation uses a sampling fraction in each of the strata that are proportional to that of the total population. For instance, if the population consists of n total individuals, m of which are male and f female (and where m + f = n), then the relative size of the two samples (x 1 = m/n males, x 2 = f/n females) should reflect this proportion.

  4. Sampling (statistics) - Wikipedia

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

    Finally, in some cases (such as designs with a large number of strata, or those with a specified minimum sample size per group), stratified sampling can potentially require a larger sample than would other methods (although in most cases, the required sample size would be no larger than would be required for simple random sampling). A ...

  5. Sample size determination - Wikipedia

    en.wikipedia.org/wiki/Sample_size_determination

    Sample size determination or estimation is the act of choosing the number of observations or replicates to include in a statistical sample. The sample size is an important feature of any empirical study in which the goal is to make inferences about a population from a sample. In practice, the sample size used in a study is usually determined ...

  6. Simple random sample - Wikipedia

    en.wikipedia.org/wiki/Simple_random_sample

    Simple random sample. In statistics, a simple random sample (or SRS) is a subset of individuals (a sample) chosen from a larger set (a population) in which a subset of individuals are chosen randomly, all with the same probability. It is a process of selecting a sample in a random way. In SRS, each subset of k individuals has the same ...

  7. Stratification (clinical trials) - Wikipedia

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

    Stratified random sampling designs divide the population into homogeneous strata, and an appropriate number of participants are chosen at random from each stratum. [1] Proportionate stratified sampling involves selecting participants from each stratum in proportions that match the general population. [ 1 ]

  8. Design effect - Wikipedia

    en.wikipedia.org/wiki/Design_effect

    Some of the more basic methods include simple random sampling (SRS, with or without replacement) and systematic sampling for getting a fixed sample size. There is also Bernoulli sampling with a random sample size. More advanced techniques such as stratified sampling and cluster sampling can also be designed to be EPSEM. For example, in cluster ...

  9. Multistage sampling - Wikipedia

    en.wikipedia.org/wiki/Multistage_sampling

    In stratified sampling, a random sample is drawn from all the strata, where in cluster sampling only the selected clusters are studied, either in single- or multi-stage. Advantages. Cost and speed that the survey can be done in; Convenience of finding the survey sample; Normally more accurate than cluster sampling for the same size sample ...