For cdf $F(x)$ ad empirical cdf $F_n(x)$, show that $|F^{-1}big(F_n(xi_p)big)-hatxi_p|overset{a.s}to0$












2












$begingroup$


Suppose $X_1,cdots,X_n$ are i.i.d. continuous random variables from distribution with cdf $F(x)$.Let $F_n(x)$
be a random variable defined by
$$F_n(x)=frac{1}nsum_{i=1}^nI{X_ile x}.$$
Define the $p$th quantile for cdf $F(x)$ as
$$xi_pequiv F^{-1}(p)=inf{x:F(x)ge p},$$
and the $p$th quantile for empirical cdf $F_n(x)$ as
$$hatxi_pequiv F_n^{-1}(p)=inf{x:F_n(x)ge p}.$$
Show that
$$Big|F^{-1}big(F_n(xi_p)big)-hatxi_pBig|overset{a.s}to0$$





How can we prove the result? By LLN, we have $F_n(x)overset{a.s}to F(x)$. Can we write the equation as
$$Big|F^{-1}big(F_n(xi_p)big)-hatxi_pBig|=Big|F^{-1}big(F_n(xi_p)big)-F_n^{-1}big(F(xi_p)big)Big|,$$
and get the result directly?










share|cite|improve this question











$endgroup$








  • 1




    $begingroup$
    For a fixed $x$, $F_n(x) = frac1n sum_{k=1}^n 1_{X_k le x}$ is a random variable with binomial distribution $Pr(F_n(x) le l/n)= sum_{m=0}^{lfloor l rfloor} {n choose m} F(x)^m (1-F(x))^m$. So $mathbb{E}[F_n(x)]= F(x)$ and $mathbb{E}[(F_n(x)-F(x))^2]= frac1n F(x)(1-F(x))to 0$. Whence $F_n(x) to F(x)$ almost surely and since $F^{-1}$ is continuous then $F^{-1}(F_n(x)) to F^{-1}(F(x))$ a.s.
    $endgroup$
    – reuns
    Dec 29 '18 at 7:38






  • 1




    $begingroup$
    @reuns The continuity of $F(x)$ does not make $F^{-1}$ continuous. Consider uniform distribution on the union of intervals $(0,1)$ and $(2,3)$ and you will get $F^{-1}(0.5)=1$, $F^{-1}(0.5+)=2$ (right limit).
    $endgroup$
    – NCh
    Dec 29 '18 at 15:15










  • $begingroup$
    Not so easy. If $F^{-1}$ is discontinuous only at finitely many point it is easier.
    $endgroup$
    – reuns
    Jan 8 at 11:27












  • $begingroup$
    @reuns Thank you for your kind comments!
    $endgroup$
    – J.Mike
    Jan 8 at 17:59
















2












$begingroup$


Suppose $X_1,cdots,X_n$ are i.i.d. continuous random variables from distribution with cdf $F(x)$.Let $F_n(x)$
be a random variable defined by
$$F_n(x)=frac{1}nsum_{i=1}^nI{X_ile x}.$$
Define the $p$th quantile for cdf $F(x)$ as
$$xi_pequiv F^{-1}(p)=inf{x:F(x)ge p},$$
and the $p$th quantile for empirical cdf $F_n(x)$ as
$$hatxi_pequiv F_n^{-1}(p)=inf{x:F_n(x)ge p}.$$
Show that
$$Big|F^{-1}big(F_n(xi_p)big)-hatxi_pBig|overset{a.s}to0$$





How can we prove the result? By LLN, we have $F_n(x)overset{a.s}to F(x)$. Can we write the equation as
$$Big|F^{-1}big(F_n(xi_p)big)-hatxi_pBig|=Big|F^{-1}big(F_n(xi_p)big)-F_n^{-1}big(F(xi_p)big)Big|,$$
and get the result directly?










share|cite|improve this question











$endgroup$








  • 1




    $begingroup$
    For a fixed $x$, $F_n(x) = frac1n sum_{k=1}^n 1_{X_k le x}$ is a random variable with binomial distribution $Pr(F_n(x) le l/n)= sum_{m=0}^{lfloor l rfloor} {n choose m} F(x)^m (1-F(x))^m$. So $mathbb{E}[F_n(x)]= F(x)$ and $mathbb{E}[(F_n(x)-F(x))^2]= frac1n F(x)(1-F(x))to 0$. Whence $F_n(x) to F(x)$ almost surely and since $F^{-1}$ is continuous then $F^{-1}(F_n(x)) to F^{-1}(F(x))$ a.s.
    $endgroup$
    – reuns
    Dec 29 '18 at 7:38






  • 1




    $begingroup$
    @reuns The continuity of $F(x)$ does not make $F^{-1}$ continuous. Consider uniform distribution on the union of intervals $(0,1)$ and $(2,3)$ and you will get $F^{-1}(0.5)=1$, $F^{-1}(0.5+)=2$ (right limit).
    $endgroup$
    – NCh
    Dec 29 '18 at 15:15










  • $begingroup$
    Not so easy. If $F^{-1}$ is discontinuous only at finitely many point it is easier.
    $endgroup$
    – reuns
    Jan 8 at 11:27












  • $begingroup$
    @reuns Thank you for your kind comments!
    $endgroup$
    – J.Mike
    Jan 8 at 17:59














2












2








2





$begingroup$


Suppose $X_1,cdots,X_n$ are i.i.d. continuous random variables from distribution with cdf $F(x)$.Let $F_n(x)$
be a random variable defined by
$$F_n(x)=frac{1}nsum_{i=1}^nI{X_ile x}.$$
Define the $p$th quantile for cdf $F(x)$ as
$$xi_pequiv F^{-1}(p)=inf{x:F(x)ge p},$$
and the $p$th quantile for empirical cdf $F_n(x)$ as
$$hatxi_pequiv F_n^{-1}(p)=inf{x:F_n(x)ge p}.$$
Show that
$$Big|F^{-1}big(F_n(xi_p)big)-hatxi_pBig|overset{a.s}to0$$





How can we prove the result? By LLN, we have $F_n(x)overset{a.s}to F(x)$. Can we write the equation as
$$Big|F^{-1}big(F_n(xi_p)big)-hatxi_pBig|=Big|F^{-1}big(F_n(xi_p)big)-F_n^{-1}big(F(xi_p)big)Big|,$$
and get the result directly?










share|cite|improve this question











$endgroup$




Suppose $X_1,cdots,X_n$ are i.i.d. continuous random variables from distribution with cdf $F(x)$.Let $F_n(x)$
be a random variable defined by
$$F_n(x)=frac{1}nsum_{i=1}^nI{X_ile x}.$$
Define the $p$th quantile for cdf $F(x)$ as
$$xi_pequiv F^{-1}(p)=inf{x:F(x)ge p},$$
and the $p$th quantile for empirical cdf $F_n(x)$ as
$$hatxi_pequiv F_n^{-1}(p)=inf{x:F_n(x)ge p}.$$
Show that
$$Big|F^{-1}big(F_n(xi_p)big)-hatxi_pBig|overset{a.s}to0$$





How can we prove the result? By LLN, we have $F_n(x)overset{a.s}to F(x)$. Can we write the equation as
$$Big|F^{-1}big(F_n(xi_p)big)-hatxi_pBig|=Big|F^{-1}big(F_n(xi_p)big)-F_n^{-1}big(F(xi_p)big)Big|,$$
and get the result directly?







probability probability-theory probability-distributions quantile






share|cite|improve this question















share|cite|improve this question













share|cite|improve this question




share|cite|improve this question








edited Jan 8 at 10:00









TZakrevskiy

20.1k12354




20.1k12354










asked Dec 29 '18 at 6:36









J.MikeJ.Mike

336110




336110








  • 1




    $begingroup$
    For a fixed $x$, $F_n(x) = frac1n sum_{k=1}^n 1_{X_k le x}$ is a random variable with binomial distribution $Pr(F_n(x) le l/n)= sum_{m=0}^{lfloor l rfloor} {n choose m} F(x)^m (1-F(x))^m$. So $mathbb{E}[F_n(x)]= F(x)$ and $mathbb{E}[(F_n(x)-F(x))^2]= frac1n F(x)(1-F(x))to 0$. Whence $F_n(x) to F(x)$ almost surely and since $F^{-1}$ is continuous then $F^{-1}(F_n(x)) to F^{-1}(F(x))$ a.s.
    $endgroup$
    – reuns
    Dec 29 '18 at 7:38






  • 1




    $begingroup$
    @reuns The continuity of $F(x)$ does not make $F^{-1}$ continuous. Consider uniform distribution on the union of intervals $(0,1)$ and $(2,3)$ and you will get $F^{-1}(0.5)=1$, $F^{-1}(0.5+)=2$ (right limit).
    $endgroup$
    – NCh
    Dec 29 '18 at 15:15










  • $begingroup$
    Not so easy. If $F^{-1}$ is discontinuous only at finitely many point it is easier.
    $endgroup$
    – reuns
    Jan 8 at 11:27












  • $begingroup$
    @reuns Thank you for your kind comments!
    $endgroup$
    – J.Mike
    Jan 8 at 17:59














  • 1




    $begingroup$
    For a fixed $x$, $F_n(x) = frac1n sum_{k=1}^n 1_{X_k le x}$ is a random variable with binomial distribution $Pr(F_n(x) le l/n)= sum_{m=0}^{lfloor l rfloor} {n choose m} F(x)^m (1-F(x))^m$. So $mathbb{E}[F_n(x)]= F(x)$ and $mathbb{E}[(F_n(x)-F(x))^2]= frac1n F(x)(1-F(x))to 0$. Whence $F_n(x) to F(x)$ almost surely and since $F^{-1}$ is continuous then $F^{-1}(F_n(x)) to F^{-1}(F(x))$ a.s.
    $endgroup$
    – reuns
    Dec 29 '18 at 7:38






  • 1




    $begingroup$
    @reuns The continuity of $F(x)$ does not make $F^{-1}$ continuous. Consider uniform distribution on the union of intervals $(0,1)$ and $(2,3)$ and you will get $F^{-1}(0.5)=1$, $F^{-1}(0.5+)=2$ (right limit).
    $endgroup$
    – NCh
    Dec 29 '18 at 15:15










  • $begingroup$
    Not so easy. If $F^{-1}$ is discontinuous only at finitely many point it is easier.
    $endgroup$
    – reuns
    Jan 8 at 11:27












  • $begingroup$
    @reuns Thank you for your kind comments!
    $endgroup$
    – J.Mike
    Jan 8 at 17:59








1




1




$begingroup$
For a fixed $x$, $F_n(x) = frac1n sum_{k=1}^n 1_{X_k le x}$ is a random variable with binomial distribution $Pr(F_n(x) le l/n)= sum_{m=0}^{lfloor l rfloor} {n choose m} F(x)^m (1-F(x))^m$. So $mathbb{E}[F_n(x)]= F(x)$ and $mathbb{E}[(F_n(x)-F(x))^2]= frac1n F(x)(1-F(x))to 0$. Whence $F_n(x) to F(x)$ almost surely and since $F^{-1}$ is continuous then $F^{-1}(F_n(x)) to F^{-1}(F(x))$ a.s.
$endgroup$
– reuns
Dec 29 '18 at 7:38




$begingroup$
For a fixed $x$, $F_n(x) = frac1n sum_{k=1}^n 1_{X_k le x}$ is a random variable with binomial distribution $Pr(F_n(x) le l/n)= sum_{m=0}^{lfloor l rfloor} {n choose m} F(x)^m (1-F(x))^m$. So $mathbb{E}[F_n(x)]= F(x)$ and $mathbb{E}[(F_n(x)-F(x))^2]= frac1n F(x)(1-F(x))to 0$. Whence $F_n(x) to F(x)$ almost surely and since $F^{-1}$ is continuous then $F^{-1}(F_n(x)) to F^{-1}(F(x))$ a.s.
$endgroup$
– reuns
Dec 29 '18 at 7:38




1




1




$begingroup$
@reuns The continuity of $F(x)$ does not make $F^{-1}$ continuous. Consider uniform distribution on the union of intervals $(0,1)$ and $(2,3)$ and you will get $F^{-1}(0.5)=1$, $F^{-1}(0.5+)=2$ (right limit).
$endgroup$
– NCh
Dec 29 '18 at 15:15




$begingroup$
@reuns The continuity of $F(x)$ does not make $F^{-1}$ continuous. Consider uniform distribution on the union of intervals $(0,1)$ and $(2,3)$ and you will get $F^{-1}(0.5)=1$, $F^{-1}(0.5+)=2$ (right limit).
$endgroup$
– NCh
Dec 29 '18 at 15:15












$begingroup$
Not so easy. If $F^{-1}$ is discontinuous only at finitely many point it is easier.
$endgroup$
– reuns
Jan 8 at 11:27






$begingroup$
Not so easy. If $F^{-1}$ is discontinuous only at finitely many point it is easier.
$endgroup$
– reuns
Jan 8 at 11:27














$begingroup$
@reuns Thank you for your kind comments!
$endgroup$
– J.Mike
Jan 8 at 17:59




$begingroup$
@reuns Thank you for your kind comments!
$endgroup$
– J.Mike
Jan 8 at 17:59










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%2f3055596%2ffor-cdf-fx-ad-empirical-cdf-f-nx-show-that-f-1-bigf-n-xi-p-big%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%2f3055596%2ffor-cdf-fx-ad-empirical-cdf-f-nx-show-that-f-1-bigf-n-xi-p-big%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

Mario Kart Wii

What does “Dominus providebit” mean?

Antonio Litta Visconti Arese