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  2. Poisson's ratio - Wikipedia

    en.wikipedia.org/wiki/Poisson's_ratio

    Poisson's ratio. In materials science and solid mechanics, Poisson's ratio ν (nu) is a measure of the Poisson effect, the deformation (expansion or contraction) of a material in directions perpendicular to the specific direction of loading. The value of Poisson's ratio is the negative of the ratio of transverse strain to axial strain.

  3. Poisson distribution - Wikipedia

    en.wikipedia.org/wiki/Poisson_distribution

    The Poisson distribution is an appropriate model if the following assumptions are true: k is the number of times an event occurs in an interval and k can take values 0, 1, 2, ... . The occurrence of one event does not affect the probability that a second event will occur. That is, events occur independently.

  4. Poisson regression - Wikipedia

    en.wikipedia.org/wiki/Poisson_regression

    v. t. e. In statistics, Poisson regression is a generalized linear model form of regression analysis used to model count data and contingency tables. [1] Poisson regression assumes the response variable Y has a Poisson distribution, and assumes the logarithm of its expected value can be modeled by a linear combination of unknown parameters.

  5. Auxetics - Wikipedia

    en.wikipedia.org/wiki/Auxetics

    Auxetics can be single molecules, crystals, or a particular structure of macroscopic matter. [ 1 ][ 2 ] Auxetic materials are used in protective equipment such as body armor, helmets, and knee pads, as they absorb energy more effectively than traditional materials. They are also used in devices such as medical stents or implants.

  6. Probability-proportional-to-size sampling - Wikipedia

    en.wikipedia.org/wiki/Probability-proportional...

    The pps sampling results in a fixed sample size n (as opposed to Poisson sampling which is similar but results in a random sample size with expectancy of n). When selecting items with replacement the selection procedure is to just draw one item at a time (like getting n draws from a multinomial distribution with N elements, each with their own ...

  7. Compound Poisson distribution - Wikipedia

    en.wikipedia.org/wiki/Compound_Poisson_distribution

    Compound Poisson distribution. In probability theory, a compound Poisson distribution is the probability distribution of the sum of a number of independent identically-distributed random variables, where the number of terms to be added is itself a Poisson-distributed variable. The result can be either a continuous or a discrete distribution.

  8. Probability mass function - Wikipedia

    en.wikipedia.org/wiki/Probability_mass_function

    The graph of a probability mass function. All the values of this function must be non-negative and sum up to 1. In probability and statistics, a probability mass function (sometimes called probability function or frequency function [1]) is a function that gives the probability that a discrete random variable is exactly equal to some value. [2]

  9. Poisson point process - Wikipedia

    en.wikipedia.org/wiki/Poisson_point_process

    A visual depiction of a Poisson point process starting. In probability theory, statistics and related fields, a Poisson point process (also known as: Poisson random measure, Poisson random point field and Poisson point field) is a type of mathematical object that consists of points randomly located on a mathematical space with the essential feature that the points occur independently of one ...