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  2. Poisson distribution - Wikipedia

    en.wikipedia.org/wiki/Poisson_distribution

    If these conditions are true, then k is a Poisson random variable; the distribution of k is a Poisson distribution. The Poisson distribution is also the limit of a binomial distribution, for which the probability of success for each trial equals λ divided by the number of trials, as the number of trials approaches infinity (see Related ...

  3. Variance - Wikipedia

    en.wikipedia.org/wiki/Variance

    Another generalization of variance for vector-valued random variables , which results in a scalar value rather than in a matrix, is the generalized variance (), the determinant of the covariance matrix. The generalized variance can be shown to be related to the multidimensional scatter of points around their mean.

  4. Probability distribution - Wikipedia

    en.wikipedia.org/wiki/Probability_distribution

    10.6 Poisson process ... the square root of the variance, ... An absolutely continuous random variable is a random variable whose probability distribution is ...

  5. Characteristic function (probability theory) - Wikipedia

    en.wikipedia.org/wiki/Characteristic_function...

    Indeed, even when the random variable does not have a density, the characteristic function may be seen as the Fourier transform of the measure corresponding to the random variable. Another related concept is the representation of probability distributions as elements of a reproducing kernel Hilbert space via the kernel embedding of distributions .

  6. Compound Poisson distribution - Wikipedia

    en.wikipedia.org/wiki/Compound_Poisson_distribution

    Here, {():} is a Poisson process with rate , and {:} are independent and identically distributed random variables, with distribution function G, which are also independent of {():}. [11] For the discrete version of compound Poisson process, it can be used in survival analysis for the frailty models.

  7. Index of dispersion - Wikipedia

    en.wikipedia.org/wiki/Index_of_dispersion

    Some distributions, most notably the Poisson distribution, have equal variance and mean, giving them a VMR = 1. The geometric distribution and the negative binomial distribution have VMR > 1, while the binomial distribution has VMR < 1, and the constant random variable has VMR = 0. This yields the following table:

  8. Random variable - Wikipedia

    en.wikipedia.org/wiki/Random_variable

    The term "random variable" in statistics is traditionally limited to the real-valued case (=). In this case, the structure of the real numbers makes it possible to define quantities such as the expected value and variance of a random variable, its cumulative distribution function, and the moments of its distribution.

  9. Poisson regression - Wikipedia

    en.wikipedia.org/wiki/Poisson_regression

    A Poisson regression model is sometimes known as a log-linear model, especially when used to model contingency tables. Negative binomial regression is a popular generalization of Poisson regression because it loosens the highly restrictive assumption that the variance is equal to the mean made by the Poisson model. The traditional negative ...