PLAYGROUND

ECUACIONES DISTRIBUCIÓN GAUSSIANA INVERSA 3P

Definición de distribución

XInverseGaussian3P(μ,λ,Loc)X\sim\mathrm{InverseGaussian_{3P}}\left(\mu,\lambda,\text{Loc}\right)

Dominio de distribución

x(0,)x\in\left(0,\infty\right)

Dominio y restricciones de parámetros

μR+,λR+,LocR\mu\in\mathbb{R}^{+},\lambda\in\mathbb{R}^{+},\text{Loc}\in\mathbb{R}

Función de distribución acumulada

FX(x)=Φ(λxLoc(xLocμ1))+exp(2λμ)Φ(λxLoc(xLocμ+1))F_{X}\left(x\right)=\Phi\left(\sqrt{\frac{\lambda}{x-\text{Loc}}}\left(\frac{x-\text{Loc}}{\mu}-1\right)\right)+\exp\left(\frac{2 \lambda}{\mu}\right) \Phi\left(-\sqrt{\frac{\lambda}{x-\text{Loc}}}\left(\frac{x-\text{Loc}}{\mu}+1\right)\right)

Función de densidad de probabilidad

fX(x)=λ2π(xLoc)3exp[λ(xμLoc)22μ2(xLoc)]f_{X}\left(x\right)=\sqrt\frac{\lambda}{2 \pi (x-\text{Loc})^3} \exp\left[-\frac{\lambda (x-\mu-\text{Loc})^2}{2 \mu^2 (x-\text{Loc})}\right]

Función de punto percentil

SampleX={Loc+x0ifu2μμ+x0Loc+μ2x0ifu2μμ+x0\text{Sample}_{X}=\left\{\begin{array}{cl} \text{Loc}+x_{0} \quad \text{if} \quad u_{2}\leqslant\frac{\mu}{\mu+x_{0}}\\ \text{Loc}+\frac{\mu^{2}}{x_{0}} \quad \text{if} \quad u_{2}\geqslant \frac{\mu}{\mu+x_{0}} \end{array} \right.

Momentos paramétricos no centrados

μk=E[Xk]=LocxkfX(x)dx\mu'_{k}=E[X^k]=\int_{\text{Loc}}^{\infty }x^{k}f_{X}\left(x\right)dx

Media paramétrica

Mean(X)=μ1=Loc+μ\mathrm{Mean}(X)=\mu'_{1}=\text{Loc}+\mu

Varianza paramétrica

Variance(X)=μ2μ12=μ3λ\mathrm{Variance}(X)=\mu'_{2}-\mu'^{2}_{1}=\frac{\mu^3}{\lambda}

Coeficiente de asimetría paramétrico

Skewness(X)=μ33μ2μ1+2μ13(μ2μ12)1.5=3(μλ)1/2\mathrm{Skewness}(X)=\frac{\mu'_{3}-3\mu'_{2}\mu'_{1}+2\mu'^{3}_{1}}{(\mu'_{2}-\mu'^{2}_{1})^{1.5}}=3\left(\frac{\mu}{\lambda}\right)^{1/2}

Curtosis paramétrica

Kurtosis(X)=μ44μ1μ3+6μ12μ23μ14(μ2μ12)2=3+15μλ\mathrm{Kurtosis}(X)=\frac{\mu'_{4}-4\mu'_{1}\mu'_{3}+6\mu'^{2}_{1}\mu'_{2}-3\mu'^{4}_{1}}{(\mu'_{2}-\mu'^{2}_{1})^{2}}=3+\frac{15 \mu}{\lambda}

Mediana paramétrica

Median(X)=FX1(12)\mathrm{Median}(X)=F^{-1}_{X}\left(\frac{1}{2}\right)

Moda paramétrica

Mode(X)=Loc+μ[(1+9μ24λ2)123μ2λ]\mathrm{Mode}(X)=\text{Loc}+\mu\left[\left(1+\frac{9 \mu^2}{4 \lambda^2}\right)^\frac{1}{2}-\frac{3 \mu}{2 \lambda}\right]

Información y definiciones adicionales

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Loc:Location parameter\text{Loc}:\text{Location parameter}
Φ(x):CDF normal standard distribution\Phi\left(x\right):\text{CDF normal standard distribution}
Φ1(x):PPF normal standard distribution\Phi^{-1}\left(x\right):\text{PPF normal standard distribution}
x0=μ+μ2[Φ1(u1)]22λμ2λ4μλ[Φ1(u1)]2+μ2([Φ1(u1)]2)2x_{0}=\mu+\frac{\mu^2 [\Phi^{-1}\left(u_{1}\right)]^{2}}{2\lambda}-\frac{\mu}{2\lambda}\sqrt{4\mu \lambda [\Phi^{-1}\left(u_{1}\right)]^{2}+\mu^2 ([\Phi^{-1}\left(u_{1}\right)]^{2})^2}
u1:Uniform[0,1] random varibleu_{1}:\text{Uniform[0,1] random varible}
u2:Uniform[0,1] random varibleu_{2}:\text{Uniform[0,1] random varible}