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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. Stratification (clinical trials) - Wikipedia

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

    Stratification (clinical trials) Stratification of clinical trials is the partitioning of subjects and results by a factor other than the treatment given. Stratification can be used to ensure equal allocation of subgroups of participants to each experimental condition. This may be done by gender, age, or other demographic factors.

  4. Cochran–Mantel–Haenszel statistics - Wikipedia

    en.wikipedia.org/wiki/Cochran–Mantel–Haenszel...

    Cochran–Mantel–Haenszel statistics. In statistics, the Cochran–Mantel–Haenszel test ( CMH) is a test used in the analysis of stratified or matched categorical data. It allows an investigator to test the association between a binary predictor or treatment and a binary outcome such as case or control status while taking into account the ...

  5. Randomized controlled trial - Wikipedia

    en.wikipedia.org/wiki/Randomized_controlled_trial

    A randomized controlled trial (or randomized control trial; [ 2] RCT) is a form of scientific experiment used to control factors not under direct experimental control. Examples of RCTs are clinical trials that compare the effects of drugs, surgical techniques, medical devices, diagnostic procedures, diets or other medical treatments. [ 3][ 4]

  6. 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.

  7. Social stratification - Wikipedia

    en.wikipedia.org/wiki/Social_stratification

    Social stratification refers to a society's categorization of its people into groups based on socioeconomic factors like wealth, income, race, education, ethnicity, gender, occupation, social status, or derived power (social and political). It is a hierarchy within groups that ascribe them to different levels of privileges. [ 1]

  8. Randomization - Wikipedia

    en.wikipedia.org/wiki/Randomization

    Randomization is a statistical process in which a random mechanism is employed to select a sample from a population or assign subjects to different groups. [ 1 ] [ 2 ] [ 3 ] The process is crucial in ensuring the random allocation of experimental units or treatment protocols, thereby minimizing selection bias and enhancing the statistical ...

  9. Selection bias - Wikipedia

    en.wikipedia.org/wiki/Selection_bias

    Selection bias. Selection bias is the bias introduced by the selection of individuals, groups, or data for analysis in such a way that proper randomization is not achieved, thereby failing to ensure that the sample obtained is representative of the population intended to be analyzed. [ 1] It is sometimes referred to as the selection effect.