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Normal

The normal (or Gaussian) distribution is a continuous probability distribution that is often used as a first approximation to describe real-valued random variables that tend to cluster around a single mean value. The graph of the associated probability density function is “bell”-shaped, and is known as the Gaussian function or bell curve. It has two parameters: parameter μ is the mean (location of the peak) and σ is the standard deviation.

This topic contains the following sections:

Constructor

Constructor

Description

Performance

set mean and standard deviation

Creates new instance of Normal with user specified parameters.

methodNormal(Double, Double)

default mean and standard deviation

Creates new instance of Normal with default parameters (0; 1).

methodNormal

set random generator

Creates new instance of Normal with user specified generator and parameters.

methodNormal(RandomGenerator, Double, Double)

Methods

Method

Description

Performance

sample

Generate random variable sample.

methodSample

Fill in array with random variable series in place:

methodSample(Double)

Static method which generates new sample of Exponential distribution variate with specified parameters:

StaticSample(Double, Double)

StaticSample(RandomGenerator, Double, Double)

pdf

Probability density function.

DNormal Pdf

methodPdf(Double)

Static probability density function.

StaticPdf(Double, Double, Double)

cdf

Cumulative distribution function.

DNormal Cdf

where erf denotes the error function.

methodCdf(Double)

Static cumulative distribution function.

StaticCdf(Double, Double, Double)

inverse cdf

Inverse cumulative distribution function. Is useful for quantile calculation. Function will return value of random variable such that likelihood for this random variable to occur less than or equal to returned value equal to specified pvalue parameter.

methodInverseCdf(Double)

StaticInverseCdf(Double, Double, Double)

Properties

Property

Description

Performance

mean

Mean of the distribution.

DNormal Mean

PropertyMean

median

Median of the distribution.

DNormal Mean

PropertyMedian

mode

Mode of distribution.

DNormal Mean

PropertyMode

kurtosis

Excess Kurtosis of distribution.

DNormal Kurtosis

PropertyKurtosis

skewness

Skewness of distribution.

DNormal Kurtosis

PropertySkewness

entropy

Entropy of distribution.

DNormal Entropy

PropertyEntropy

variance

Variance of the distribution.

DNormal Variance

PropertyVariance

standard deviation

Standard deviation of the distribution.

DNormal Std Dev

PropertyStandardDeviation

method

Method of normal distribution generation.

Method may take values:

  • BOXMULLER

    generates normally distributed random number x through the pair of uniformly distributed numbers u1 and u2 according to the formula: DBoxmuller

  • BOXMULLER2

    generates normally distributed random numbers x1 and x2 through the pair of uniformly distributed numbers u1 and u2 according to the formulas:

    DBoxmuller 21 and DBoxmuller 22

  • Inverse cumulative distribution function method.

PropertyMethod