/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 6 Let \(X\) have a generalized Par... [FREE SOLUTION] | 91Ó°ÊÓ

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Let \(X\) have a generalized Pareto distribution with parameters \(k, \alpha\), and \(\beta\). Show, by change of variables, that \(Y=\beta X /(1+\beta X)\) has a beta distribution.

Short Answer

Expert verified
By changing the variables and transforming the generalized Pareto distribution, \(Y = \frac{\beta X}{1+\beta X} \) followed a beta distribution. This was confirmed by transforming and simplifying the pdf.

Step by step solution

01

Setup the Problem

Firstly, understand that you are given \(X\) with a generalized Pareto distribution, and the task is to prove that the variable \(Y=\beta X /(1+\beta X)\) follows a Beta distribution.
02

Performing a Change of Variables

To start with this problem, one must first perform a change of variable from \(X\) to \(Y\). Therefore, let's solve the equation \(Y=\beta X /(1+\beta X)\) for \(X\), which will give us \(X=Y/(1-Y)\). Now we can write the pdf of \(X\) in terms of \(Y\). Derivative of \(X\) with respect to \(Y\) gives \(\frac {dX}{dY} = \frac {1} {(1-Y)^2}\), which is necessary for the transformation.
03

Getting the pdf of Y

Now you have to find the pdf of \(Y\) by substituting the transformation of \(X\) from Step 2 into the pdf of \(X\). Once done, multiply the result with absolute value of \(\frac {dX}{dY}\). The pdf of \(X\) for a generalized Pareto distribution is given by \(f_X (x) = \frac {1} {\beta} (1 + kx/\beta)^{-(1+k)/\alpha}\) for \(x>0\). Therefore, the pdf of \(Y\) will be \(f_Y (y) = |(\frac {dX}{dY})| * f_X (x)\), where \(x = y/(1-y)\).
04

Simplifying the pdf of Y

Here, the challenge is to simplify the expression of \(f_Y (y)\) to show that it is equivalent to the pdf of a Beta distribution. Work through the simplification and you should find the pdf of the Beta distribution.

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