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  2. 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.

  3. Stratified sampling - Wikipedia

    en.wikipedia.org/wiki/Stratified_sampling

    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.

  4. 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 ...

  5. Training, validation, and test data sets - Wikipedia

    en.wikipedia.org/wiki/Training,_validation,_and...

    Finally, the test data set is a data set used to provide an unbiased evaluation of a final model fit on the training data set. [5] If the data in the test data set has never been used in training (for example in cross-validation), the test data set is also called a holdout data set. The term "validation set" is sometimes used instead of "test ...

  6. A/B testing - Wikipedia

    en.wikipedia.org/wiki/A/B_testing

    A/B testing (also known as bucket testing, split-run testing, or split testing) is a user experience research method. [1] A/B tests consist of a randomized experiment that usually involves two variants (A and B), [ 2 ] [ 3 ] [ 4 ] although the concept can be also extended to multiple variants of the same variable.

  7. Population structure (genetics) - Wikipedia

    en.wikipedia.org/wiki/Population_structure...

    Population structure (also called genetic structure and population stratification) is the presence of a systematic difference in allele frequencies between subpopulations. In a randomly mating (or panmictic) population, allele frequencies are expected to be roughly similar between groups. However, mating tends to be non-random to some degree ...

  8. Leakage (machine learning) - Wikipedia

    en.wikipedia.org/wiki/Leakage_(machine_learning)

    t. e. In statistics and machine learning, leakage (also known as data leakage or target leakage) is the use of information in the model training process which would not be expected to be available at prediction time, causing the predictive scores (metrics) to overestimate the model's utility when run in a production environment. [1]

  9. Transportation Technology Center - Wikipedia

    en.wikipedia.org/wiki/Transportation_Technology...

    The prominent buildings on the right side of the photograph are the RDL (foreground) and CSB (background). The Transportation Technology Center (TTC) is a railroad equipment testing and training facility located northeast of Pueblo, Colorado, owned by the Federal Railroad Administration (FRA). It was built in 1971 as the High Speed Ground Test ...