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  2. Natural density - Wikipedia

    en.wikipedia.org/wiki/Natural_density

    A subset A of positive integers has natural density α if the proportion of elements of A among all natural numbers from 1 to n converges to α as n tends to infinity.. More explicitly, if one defines for any natural number n the counting function a(n) as the number of elements of A less than or equal to n, then the natural density of A being α exactly means that [1]

  3. Probability density function - Wikipedia

    en.wikipedia.org/wiki/Probability_density_function

    In the field of statistical physics, a non-formal reformulation of the relation above between the derivative of the cumulative distribution function and the probability density function is generally used as the definition of the probability density function. This alternate definition is the following: If dt is an infinitely small number, the ...

  4. Dependent and independent variables - Wikipedia

    en.wikipedia.org/wiki/Dependent_and_independent...

    In mathematics, a function is a rule for taking an input (in the simplest case, a number or set of numbers) [5] and providing an output (which may also be a number). [5] A symbol that stands for an arbitrary input is called an independent variable, while a symbol that stands for an arbitrary output is called a dependent variable. [6]

  5. Copula (statistics) - Wikipedia

    en.wikipedia.org/wiki/Copula_(statistics)

    when the two marginal functions and the copula density function are known, then the joint probability density function between the two random variables can be calculated, or; when the two marginal functions and the joint probability density function between the two random variables are known, then the copula density function can be calculated.

  6. Convolution of probability distributions - Wikipedia

    en.wikipedia.org/wiki/Convolution_of_probability...

    The probability distribution of the sum of two or more independent random variables is the convolution of their individual distributions. The term is motivated by the fact that the probability mass function or probability density function of a sum of independent random variables is the convolution of their corresponding probability mass functions or probability density functions respectively.

  7. Density dependence - Wikipedia

    en.wikipedia.org/wiki/Density_dependence

    Density-dependent fecundity. Density-dependent fecundity exists, where the birth rate falls as competition increases. In the context of gastrointestinal nematodes, the weight of female Ascaris lumbricoides and its rates of egg production decrease as host infection intensity increases. Thus, the per-capita contribution of each worm to ...

  8. Complex random variable - Wikipedia

    en.wikipedia.org/wiki/Complex_random_variable

    Another example of a complex random variable is the uniform distribution over the filled unit circle, i.e. the set {| |}. This random variable is an example of a complex random variable for which the probability density function is defined. The density function is shown as the yellow disk and dark blue base in the following figure.

  9. Likelihood function - Wikipedia

    en.wikipedia.org/wiki/Likelihood_function

    In measure-theoretic probability theory, the density function is defined as the Radon–Nikodym derivative of the probability distribution relative to a common dominating measure. [5] The likelihood function is this density interpreted as a function of the parameter, rather than the random variable. [6]