using Central Limit Theorem to approximate a probability with large 'n'












1












$begingroup$


For $i>1$ , let $X_i$ ~ $G_{1/2}$ be distributed Geometrically with parameter $1/2$.



$$ Y_n= frac{1}{sqrt n} sum_{r=1}^n X_r-2 $$



Approximate $P(-1le Y_nle 2)$ with large n.($Y_n$ is not properly normalized)



My attempt-

normalised $Y_n = frac{1}{sqrt n} sum_{r=1}^n frac{(X_r-2)-E[X_r-2]}{V[X-2]*n}$



then approximating $P(-1le Y_nle 2)$ I got the answer as 0.4332 which is incorrect. Can anybody give me the correct solution of this question.










share|cite|improve this question









$endgroup$












  • $begingroup$
    @Damandeep Its an online course in probability and stats
    $endgroup$
    – Kriti Arora
    Dec 14 '18 at 11:43
















1












$begingroup$


For $i>1$ , let $X_i$ ~ $G_{1/2}$ be distributed Geometrically with parameter $1/2$.



$$ Y_n= frac{1}{sqrt n} sum_{r=1}^n X_r-2 $$



Approximate $P(-1le Y_nle 2)$ with large n.($Y_n$ is not properly normalized)



My attempt-

normalised $Y_n = frac{1}{sqrt n} sum_{r=1}^n frac{(X_r-2)-E[X_r-2]}{V[X-2]*n}$



then approximating $P(-1le Y_nle 2)$ I got the answer as 0.4332 which is incorrect. Can anybody give me the correct solution of this question.










share|cite|improve this question









$endgroup$












  • $begingroup$
    @Damandeep Its an online course in probability and stats
    $endgroup$
    – Kriti Arora
    Dec 14 '18 at 11:43














1












1








1





$begingroup$


For $i>1$ , let $X_i$ ~ $G_{1/2}$ be distributed Geometrically with parameter $1/2$.



$$ Y_n= frac{1}{sqrt n} sum_{r=1}^n X_r-2 $$



Approximate $P(-1le Y_nle 2)$ with large n.($Y_n$ is not properly normalized)



My attempt-

normalised $Y_n = frac{1}{sqrt n} sum_{r=1}^n frac{(X_r-2)-E[X_r-2]}{V[X-2]*n}$



then approximating $P(-1le Y_nle 2)$ I got the answer as 0.4332 which is incorrect. Can anybody give me the correct solution of this question.










share|cite|improve this question









$endgroup$




For $i>1$ , let $X_i$ ~ $G_{1/2}$ be distributed Geometrically with parameter $1/2$.



$$ Y_n= frac{1}{sqrt n} sum_{r=1}^n X_r-2 $$



Approximate $P(-1le Y_nle 2)$ with large n.($Y_n$ is not properly normalized)



My attempt-

normalised $Y_n = frac{1}{sqrt n} sum_{r=1}^n frac{(X_r-2)-E[X_r-2]}{V[X-2]*n}$



then approximating $P(-1le Y_nle 2)$ I got the answer as 0.4332 which is incorrect. Can anybody give me the correct solution of this question.







statistics central-limit-theorem






share|cite|improve this question













share|cite|improve this question











share|cite|improve this question




share|cite|improve this question










asked Dec 8 '18 at 10:15









Kriti AroraKriti Arora

396




396












  • $begingroup$
    @Damandeep Its an online course in probability and stats
    $endgroup$
    – Kriti Arora
    Dec 14 '18 at 11:43


















  • $begingroup$
    @Damandeep Its an online course in probability and stats
    $endgroup$
    – Kriti Arora
    Dec 14 '18 at 11:43
















$begingroup$
@Damandeep Its an online course in probability and stats
$endgroup$
– Kriti Arora
Dec 14 '18 at 11:43




$begingroup$
@Damandeep Its an online course in probability and stats
$endgroup$
– Kriti Arora
Dec 14 '18 at 11:43










1 Answer
1






active

oldest

votes


















1












$begingroup$

Like $X_r-2$, $Y_n$ has mean $0$ and variance $2$. The answer is therefore $Phi(sqrt{2})-Phi(frac{-1}{sqrt{2}})approx 0.6816$.






share|cite|improve this answer









$endgroup$













    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%2f3030916%2fusing-central-limit-theorem-to-approximate-a-probability-with-large-n%23new-answer', 'question_page');
    }
    );

    Post as a guest















    Required, but never shown

























    1 Answer
    1






    active

    oldest

    votes








    1 Answer
    1






    active

    oldest

    votes









    active

    oldest

    votes






    active

    oldest

    votes









    1












    $begingroup$

    Like $X_r-2$, $Y_n$ has mean $0$ and variance $2$. The answer is therefore $Phi(sqrt{2})-Phi(frac{-1}{sqrt{2}})approx 0.6816$.






    share|cite|improve this answer









    $endgroup$


















      1












      $begingroup$

      Like $X_r-2$, $Y_n$ has mean $0$ and variance $2$. The answer is therefore $Phi(sqrt{2})-Phi(frac{-1}{sqrt{2}})approx 0.6816$.






      share|cite|improve this answer









      $endgroup$
















        1












        1








        1





        $begingroup$

        Like $X_r-2$, $Y_n$ has mean $0$ and variance $2$. The answer is therefore $Phi(sqrt{2})-Phi(frac{-1}{sqrt{2}})approx 0.6816$.






        share|cite|improve this answer









        $endgroup$



        Like $X_r-2$, $Y_n$ has mean $0$ and variance $2$. The answer is therefore $Phi(sqrt{2})-Phi(frac{-1}{sqrt{2}})approx 0.6816$.







        share|cite|improve this answer












        share|cite|improve this answer



        share|cite|improve this answer










        answered Dec 8 '18 at 10:27









        J.G.J.G.

        26.3k22541




        26.3k22541






























            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%2f3030916%2fusing-central-limit-theorem-to-approximate-a-probability-with-large-n%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

            Plaza Victoria

            In PowerPoint, is there a keyboard shortcut for bulleted / numbered list?

            How to put 3 figures in Latex with 2 figures side by side and 1 below these side by side images but in...