S chart - An S chart is a statistical process control chart that plots the sample standard deviation within successive subgroups.
S metric - The s metric is a graph statistic obtained by summing the product of the endpoint degrees over all edges.
S-set - The S-set is the specific boundary of a version space: the set of maximally specific hypotheses that remain consistent with all observed training examples.
Safe policy iteration - Safe policy iteration is a family of reinforcement-learning and approximate dynamic-programming methods that choose policy updates by maximizing a lower...
Safety - Safety is the condition and practice of preventing unacceptable harm from a system's operation, failures, or interactions with its surroundings.
Saliency - In visual perception and computer vision, saliency describes how strongly a location or feature stands out within a scene under a stated model of attention.
Salt-and-pepper noise - Salt-and-pepper noise is an image corruption pattern in which affected samples take very low or very high intensity values, often appearing as scattered...
Sammon mapping - Sammon mapping is a nonlinear dimensionality-reduction method that places observations in a lower-dimensional space while trying to preserve their pairwise...
Sample - A sample is a collection of units or observations selected from a population or generated by a specified data-collection process.
Sample augmentation - Sample augmentation, in survey statistics, means maintaining and adding units to an existing sample so that it continues to cover the evolving population...
Sample complexity - Sample complexity describes how many observations a learning or estimation procedure needs to meet a specified performance criterion under stated assumptions.
Sample frame - A sample frame, more commonly called a sampling frame, is the list, map, register, or other operational device used to identify and access units for sample...
Sample mean - The sample mean is the arithmetic average of the observed values of a numeric variable.
Sample ratio mismatch - Sample ratio mismatch, abbreviated SRM, is a statistically significant discrepancy between the observed numbers of experimental units in treatment groups...
Sample rotation - Sample rotation is the planned replacement of some or all units in a recurring survey sample after a specified period of participation.
Sample size - Sample size is the number of units or observations included in a defined sample, usually denoted n.
Sample size determination - Sample size determination is the process of choosing how many units or observations a study needs to meet a defined objective under stated assumptions.
Sample size disparity - Sample size disparity is a difference in the number of available observations across groups.
Sample space - A sample space is the set of all possible outcomes represented by a probability model for an experiment or random process. It is commonly denoted S or Omega.
Sample Standard Deviation - The sample standard deviation measures the spread of observed numerical values around their sample mean.
Sample statistics - Sample statistics are quantities calculated from observed sample data, such as a mean, median, proportion, variance, or correlation.
Sample unique - A sample unique is a record whose combination of specified key-variable values occurs only once within a dataset.
Sample variance - Sample variance is a measure of how widely observations are dispersed around their sample mean.
Sample weighting - Sample weighting assigns different numerical contributions to observations when calculating estimates, fitting models, or evaluating performance.
Sampled softmax - Sampled softmax is a training method that approximates a large softmax classification problem using the true target classes and a sampled subset of...
Sampling - Sampling means drawing an outcome according to a probability distribution.
Sampling bias - Sampling bias is systematic distortion arising when the process used to collect a sample gives an unrepresentative view of the population or task of interest.
Sampling design - Sampling design is the set of rules specifying how units are selected from a population or sampling frame.
Sampling distribution - A sampling distribution is the probability distribution of a statistic across the samples that could arise from a specified population and sampling process.
Sampling distribution of differences between means - The sampling distribution of differences between means is the probability distribution of a difference between sample averages over repeated samples drawn...
Sampling distribution of the mean - The sampling distribution of the mean is the probability distribution of the averages produced by repeated samples under a specified population model and...
Sampling error - Sampling error is the random variation in an estimate that arises because information is collected from a sample rather than the entire target population.
Sampling fraction - The sampling fraction is the proportion of a defined finite population selected into a sample, commonly written f = n/N, where n is the sample size and N is...
Sampling probability - Sampling probability, in finite-population sampling, usually means a unit's inclusion probability: the probability that it appears in the sample under the...
Sampling rate - Sampling rate is the number of signal measurements taken or represented per second, usually expressed in hertz.
Sampling risk - Sampling risk is the possibility that a conclusion based on a sample differs from the conclusion obtained by applying the same examination procedure to the...
Sampling with replacement - Sampling with replacement is a selection procedure in which an item remains eligible to be selected again after it has been drawn.
Sardinas - Patterson algorithm - The Sardinas - Patterson algorithm determines whether a finite set of variable-length codewords is uniquely decodable.
SARSA - SARSA is an on-policy temporal-difference reinforcement-learning algorithm that updates an action-value estimate using the next action actually selected by...
SARSA(lambda) - SARSA(lambda) is an on-policy reinforcement-learning control method that extends one-step SARSA with eligibility traces.
SAT - SAT is the Boolean satisfiability decision problem: given a propositional formula, determine whether some assignment of true or false values to its...
Satellite image time series - A satellite image time series is a sequence of satellite observations of an area, ordered by acquisition time and prepared so that measurements can be...
Satisfiability - Satisfiability is the property of a logical formula or collection of constraints being true under at least one permitted interpretation.
Satisfiability threshold conjecture - The satisfiability threshold conjecture is the historical claim that, for each fixed clause size k in a standard random k-SAT model, a constant...
Satisficing - Satisficing is a decision strategy that seeks an option meeting an acceptable standard and can stop searching once such an option is found.
Satterthwaite solution - The Satterthwaite solution is an approximation used to assign effective degrees of freedom when an estimated variance combines contributions with different...