2-level designs - Two-level designs are experimental designs in which each studied factor is assigned two specified settings, often called low and high.
Abductive reasoning - Abductive reasoning generates or selects plausible explanations for observations.
Abess - Abess, short for Adaptive Best Subset Selection, is a method and software library for selecting a small subset of predictors while fitting a statistical model.
Absolute frequency - Absolute frequency is the number of times a specified value, category, or event occurs in a defined dataset.
ABX test - An ABX test is a discrimination test in which a participant compares known references A and B with an unidentified sample X and decides whether X matches A...
Accelerated failure time model - An accelerated failure time model, or AFT model, relates explanatory variables to the time until an event by stretching or compressing the time scale.
Acceptable quality limit - Acceptable quality limit is a term commonly associated with AQL, a quality level used to select or describe acceptance-sampling schemes.
Acceptance probability - Acceptance probability is the probability that an algorithm accepts a proposed candidate, given its current state and decision rule.
Acceptance sampling - Acceptance sampling is a procedure for deciding what to do with a lot or batch by inspecting a sample rather than every item.
ACE model - The ACE model is a statistical model that partitions variation in an observed trait into additive genetic variance (A), shared environmental variance (C)...
Acquiescence bias - Acquiescence bias is a response tendency to agree with statements regardless of their specific content.
Ad hoc survey - An ad hoc survey is a survey undertaken without a plan to repeat it.
Adaptive design (medicine) - An adaptive design in medicine is a clinical-trial design that permits specified changes based on accumulating trial data according to a plan established in...
Additive effect - An additive effect is a modeled change in the expected response from changing one input factor that does not depend on the settings of other input factors.
Additive law of probability - The additive law of probability states that the probability of one of several mutually exclusive events occurring is the sum of their individual probabilities.
Additive model - An additive model represents an outcome as a sum of component contributions.
Adjacent values - Adjacent values are the most extreme observed data values that remain within the inner fences of a conventional Tukey-style box plot.
Adjusted correlation ( r adj ) - Adjusted correlation, in the source glossary's regression sense, is a correlation measure corrected for the number of predictors relative to the sample size.
Adjusted means - Adjusted means are model-based group averages calculated after accounting for specified covariates or other predictors.
Adjusting or controlling for a variable - Adjusting or controlling for a variable means accounting for that variable when assessing the relationship between other variables.
Administrative data - Administrative data are records created as organizations carry out routine operations, deliver services or administer programs.
Administrative data collection - Administrative data collection is the organized acquisition and processing of data from administrative sources for statistical purposes.
Admissible decision rule - An admissible decision rule is a statistical rule that is not dominated by another allowed rule under a specified model and loss function.
Affine calibration - Affine calibration, in the source glossary's computer-experiment sense, improves agreement between simulated and observed responses by applying an affine...
Age adjustment - Age adjustment is a statistical method for comparing populations while accounting for differences in their age distributions.
Aliasing (factorial experiments) - Aliasing in factorial experiments occurs when the chosen experimental runs do not allow some effects to be estimated separately.
All-pairs testing - All-pairs testing, also called pairwise testing, is a combinatorial software-testing method that ensures every relevant combination of values for every pair...
Allocation concealment - Allocation concealment is the protection of upcoming treatment assignments from people enrolling participants in a randomized trial until assignment occurs.
Allocation ratio - The allocation ratio is the intended relative number of participants assigned to comparison groups in a trial.
Almost sure hypothesis testing - Almost sure hypothesis testing studies sequences of tests whose decisions eventually remain correct with probability one as observations accumulate, under...
Alternative hypothesis - An alternative hypothesis is the statistical claim considered in contrast to a null hypothesis.
Analysis of covariance - Analysis of covariance, or ANCOVA, is a regression-based method for comparing groups while including one or more quantitative covariates.
Analysis of manufacturing variance - Analysis of manufacturing variance, or AMV, is a computer-experiment approach that decomposes projected manufacturing-process variation into contributions...
Analysis of rhythmic variance - Analysis of rhythmic variance, abbreviated ANORVA, is a method proposed by Peter Celec for detecting periodic patterns in biological time series.
Analysis of similarities - Analysis of similarities, or ANOSIM, is a permutation-based statistical method for comparing predefined groups using ranked pairwise dissimilarities.
Analysis of variance - Analysis of variance, or ANOVA, is a family of statistical methods that partitions variation in an outcome into components associated with modeled factors...
Analytic survey - An analytic survey is a sample survey designed primarily to compare sectors or subgroups within the sampled population.
Ancestral graph - An ancestral graph is a mixed graph used to represent conditional independence relationships, allowing directed, bidirected and undirected edges under...
Anderson-Darling test - The Anderson-Darling test is a goodness-of-fit test that compares an empirical distribution with a specified distribution or fitted distribution family.
Ansari-Bradley test - The Ansari-Bradley test is a rank-based test for a difference in scale between two independent samples.
Antecedent variable - An antecedent variable is a variable that precedes another variable in time or in a proposed explanatory sequence.
Antithetic variates - Antithetic variates are a Monte Carlo variance-reduction technique that pairs simulated outputs with deliberately related counterparts.
Appearance model - An appearance model is a representation of how an object, region or scene looks in images and how that visual evidence can vary.
Approximate Bayesian computation - Approximate Bayesian computation (ABC) is a family of methods for learning about model parameters by comparing simulated data with observations when...
Approximate entropy - Approximate entropy (ApEn) is a statistic that describes the regularity of a finite sequence by comparing the frequency of similar patterns with the...
Arc standard - Arc standard, usually written arc-standard, is a transition system for building dependency parses of sentences.
Area sampling - Area sampling is survey sampling in which geographical areas serve as sampling units at one or more stages.
Area sampling frame - An area sampling frame is an organized representation of geographical sampling units from which a survey sample can be selected.