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  2. Kolmogorov–Smirnov test - Wikipedia

    en.wikipedia.org/wiki/Kolmogorov–Smirnov_test

    Illustration of the Kolmogorov–Smirnov statistic. The red line is a model CDF, the blue line is an empirical CDF, and the black arrow is the KS statistic.. In statistics, the Kolmogorov–Smirnov test (also K–S test or KS test) is a nonparametric test of the equality of continuous (or discontinuous, see Section 2.2), one-dimensional probability distributions.

  3. Tuple relational calculus - Wikipedia

    en.wikipedia.org/wiki/Tuple_relational_calculus

    if v in V, a in type(v) and k denotes a value in D then the formula v.a = k is in A[S,type], and; if v in V, r in R and type(v) = h(r) then the formula r(v) is in A[S,type]. Examples of atoms are: (t.age = s.age) — t has an age attribute and s has an age attribute with the same value (t.name = "Codd") — tuple t has a name attribute and its ...

  4. List of probability distributions - Wikipedia

    en.wikipedia.org/wiki/List_of_probability...

    It is ubiquitous in nature and statistics due to the central limit theorem: every variable that can be modelled as a sum of many small independent, identically distributed variables with finite mean and variance is approximately normal. The normal-exponential-gamma distribution; The normal-inverse Gaussian distribution

  5. K-distribution - Wikipedia

    en.wikipedia.org/wiki/K-distribution

    K-distribution arises as the consequence of a statistical or probabilistic model used in synthetic-aperture radar (SAR) imagery. The K-distribution is formed by compounding two separate probability distributions, one representing the radar cross-section, and the other representing speckle that is a characteristic of coherent imaging. It is also ...

  6. Aggregate function - Wikipedia

    en.wikipedia.org/wiki/Aggregate_function

    Nanmean (mean ignoring NaN values, also known as "nil" or "null") Stddev; Formally, an aggregate function takes as input a set, a multiset (bag), or a list from some input domain I and outputs an element of an output domain O. [1] The input and output domains may be the same, such as for SUM, or may be different, such as for COUNT.

  7. Statistical model - Wikipedia

    en.wikipedia.org/wiki/Statistical_model

    In this example, the dimension, k, equals 2. As another example, suppose that the data consists of points (x, y) that we assume are distributed according to a straight line with i.i.d. Gaussian residuals (with zero mean): this leads to the same statistical model as was used in the example with children's heights. The dimension of the ...

  8. Quantile - Wikipedia

    en.wikipedia.org/wiki/Quantile

    For a population, of discrete values or for a continuous population density, the k-th q-quantile is the data value where the cumulative distribution function crosses k/q. That is, x is a k-th q-quantile for a variable X if Pr[X < x] ≤ k/q or, equivalently, Pr[X ≥ x] ≥ 1 − k/q. and Pr[X ≤ x] ≥ k/q.

  9. Statistical data type - Wikipedia

    en.wikipedia.org/wiki/Statistical_data_type

    For example, count data requires a different distribution (e.g. a Poisson distribution or binomial distribution) than non-negative real-valued data require, but both fall under the same level of measurement (a ratio scale). Various attempts have been made to produce a taxonomy of levels of measurement.