Probability density function (PDF) of a scaled non-central chi squared distribution












0












$begingroup$


I know that:




  1. If $X$ is exponentially distributed with a rate parameter $lambda$, then $cX$ is exponentially distributed with a rate parameter $frac{lambda}{c}$.


  2. If $X$ is central chi-squared distributed with $nu$ degree of freedom, then $cX$ is gamma distributed with shape $frac{nu}{2}$ and scale parameter $2c$.



where $c$ is a positive constant.
My question is:



If $X$ is non-central chi-squared distributed with $nu$ degree of freedom, then how is $cX$ distributed? What is the pdf of $cX$ ?










share|cite|improve this question









$endgroup$












  • $begingroup$
    In general, the PDF of $cX$ is $frac{1}{c} f_X(t/c)$ where $f_X$ is the PDF of $X$. I don't know of a nice name for the distribution of your particular $cX$ though.
    $endgroup$
    – angryavian
    Jan 1 at 5:48










  • $begingroup$
    Thank you @angryavian. The information you gave is very helpful. By the way, is there a reference where the PDF of $cX$ is $frac{1}{c}f_X(frac{t}{c}) $?
    $endgroup$
    – M.A.N
    Jan 1 at 7:07










  • $begingroup$
    This is a special case of change of variables.
    $endgroup$
    – angryavian
    Jan 1 at 17:22
















0












$begingroup$


I know that:




  1. If $X$ is exponentially distributed with a rate parameter $lambda$, then $cX$ is exponentially distributed with a rate parameter $frac{lambda}{c}$.


  2. If $X$ is central chi-squared distributed with $nu$ degree of freedom, then $cX$ is gamma distributed with shape $frac{nu}{2}$ and scale parameter $2c$.



where $c$ is a positive constant.
My question is:



If $X$ is non-central chi-squared distributed with $nu$ degree of freedom, then how is $cX$ distributed? What is the pdf of $cX$ ?










share|cite|improve this question









$endgroup$












  • $begingroup$
    In general, the PDF of $cX$ is $frac{1}{c} f_X(t/c)$ where $f_X$ is the PDF of $X$. I don't know of a nice name for the distribution of your particular $cX$ though.
    $endgroup$
    – angryavian
    Jan 1 at 5:48










  • $begingroup$
    Thank you @angryavian. The information you gave is very helpful. By the way, is there a reference where the PDF of $cX$ is $frac{1}{c}f_X(frac{t}{c}) $?
    $endgroup$
    – M.A.N
    Jan 1 at 7:07










  • $begingroup$
    This is a special case of change of variables.
    $endgroup$
    – angryavian
    Jan 1 at 17:22














0












0








0





$begingroup$


I know that:




  1. If $X$ is exponentially distributed with a rate parameter $lambda$, then $cX$ is exponentially distributed with a rate parameter $frac{lambda}{c}$.


  2. If $X$ is central chi-squared distributed with $nu$ degree of freedom, then $cX$ is gamma distributed with shape $frac{nu}{2}$ and scale parameter $2c$.



where $c$ is a positive constant.
My question is:



If $X$ is non-central chi-squared distributed with $nu$ degree of freedom, then how is $cX$ distributed? What is the pdf of $cX$ ?










share|cite|improve this question









$endgroup$




I know that:




  1. If $X$ is exponentially distributed with a rate parameter $lambda$, then $cX$ is exponentially distributed with a rate parameter $frac{lambda}{c}$.


  2. If $X$ is central chi-squared distributed with $nu$ degree of freedom, then $cX$ is gamma distributed with shape $frac{nu}{2}$ and scale parameter $2c$.



where $c$ is a positive constant.
My question is:



If $X$ is non-central chi-squared distributed with $nu$ degree of freedom, then how is $cX$ distributed? What is the pdf of $cX$ ?







statistics probability-distributions






share|cite|improve this question













share|cite|improve this question











share|cite|improve this question




share|cite|improve this question










asked Jan 1 at 4:18









M.A.NM.A.N

1078




1078












  • $begingroup$
    In general, the PDF of $cX$ is $frac{1}{c} f_X(t/c)$ where $f_X$ is the PDF of $X$. I don't know of a nice name for the distribution of your particular $cX$ though.
    $endgroup$
    – angryavian
    Jan 1 at 5:48










  • $begingroup$
    Thank you @angryavian. The information you gave is very helpful. By the way, is there a reference where the PDF of $cX$ is $frac{1}{c}f_X(frac{t}{c}) $?
    $endgroup$
    – M.A.N
    Jan 1 at 7:07










  • $begingroup$
    This is a special case of change of variables.
    $endgroup$
    – angryavian
    Jan 1 at 17:22


















  • $begingroup$
    In general, the PDF of $cX$ is $frac{1}{c} f_X(t/c)$ where $f_X$ is the PDF of $X$. I don't know of a nice name for the distribution of your particular $cX$ though.
    $endgroup$
    – angryavian
    Jan 1 at 5:48










  • $begingroup$
    Thank you @angryavian. The information you gave is very helpful. By the way, is there a reference where the PDF of $cX$ is $frac{1}{c}f_X(frac{t}{c}) $?
    $endgroup$
    – M.A.N
    Jan 1 at 7:07










  • $begingroup$
    This is a special case of change of variables.
    $endgroup$
    – angryavian
    Jan 1 at 17:22
















$begingroup$
In general, the PDF of $cX$ is $frac{1}{c} f_X(t/c)$ where $f_X$ is the PDF of $X$. I don't know of a nice name for the distribution of your particular $cX$ though.
$endgroup$
– angryavian
Jan 1 at 5:48




$begingroup$
In general, the PDF of $cX$ is $frac{1}{c} f_X(t/c)$ where $f_X$ is the PDF of $X$. I don't know of a nice name for the distribution of your particular $cX$ though.
$endgroup$
– angryavian
Jan 1 at 5:48












$begingroup$
Thank you @angryavian. The information you gave is very helpful. By the way, is there a reference where the PDF of $cX$ is $frac{1}{c}f_X(frac{t}{c}) $?
$endgroup$
– M.A.N
Jan 1 at 7:07




$begingroup$
Thank you @angryavian. The information you gave is very helpful. By the way, is there a reference where the PDF of $cX$ is $frac{1}{c}f_X(frac{t}{c}) $?
$endgroup$
– M.A.N
Jan 1 at 7:07












$begingroup$
This is a special case of change of variables.
$endgroup$
– angryavian
Jan 1 at 17:22




$begingroup$
This is a special case of change of variables.
$endgroup$
– angryavian
Jan 1 at 17:22










0






active

oldest

votes











Your Answer





StackExchange.ifUsing("editor", function () {
return StackExchange.using("mathjaxEditing", function () {
StackExchange.MarkdownEditor.creationCallbacks.add(function (editor, postfix) {
StackExchange.mathjaxEditing.prepareWmdForMathJax(editor, postfix, [["$", "$"], ["\\(","\\)"]]);
});
});
}, "mathjax-editing");

StackExchange.ready(function() {
var channelOptions = {
tags: "".split(" "),
id: "69"
};
initTagRenderer("".split(" "), "".split(" "), channelOptions);

StackExchange.using("externalEditor", function() {
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled) {
StackExchange.using("snippets", function() {
createEditor();
});
}
else {
createEditor();
}
});

function createEditor() {
StackExchange.prepareEditor({
heartbeatType: 'answer',
autoActivateHeartbeat: false,
convertImagesToLinks: true,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: 10,
bindNavPrevention: true,
postfix: "",
imageUploader: {
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
},
noCode: true, onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
});


}
});














draft saved

draft discarded


















StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f3058215%2fprobability-density-function-pdf-of-a-scaled-non-central-chi-squared-distribut%23new-answer', 'question_page');
}
);

Post as a guest















Required, but never shown

























0






active

oldest

votes








0






active

oldest

votes









active

oldest

votes






active

oldest

votes
















draft saved

draft discarded




















































Thanks for contributing an answer to Mathematics Stack Exchange!


  • Please be sure to answer the question. Provide details and share your research!

But avoid



  • Asking for help, clarification, or responding to other answers.

  • Making statements based on opinion; back them up with references or personal experience.


Use MathJax to format equations. MathJax reference.


To learn more, see our tips on writing great answers.




draft saved


draft discarded














StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f3058215%2fprobability-density-function-pdf-of-a-scaled-non-central-chi-squared-distribut%23new-answer', 'question_page');
}
);

Post as a guest















Required, but never shown





















































Required, but never shown














Required, but never shown












Required, but never shown







Required, but never shown

































Required, but never shown














Required, but never shown












Required, but never shown







Required, but never shown







Popular posts from this blog

Probability when a professor distributes a quiz and homework assignment to a class of n students.

Aardman Animations

Are they similar matrix