Expectation of k-th order statistic of Negative Binomial Distribution












0












$begingroup$


Let $ X_1, X_2,...$ be i.i.d $NB(k,q)$. I am interested in calculating the expectation of their k-th order statistic $X_{k:n}$. From my understanding of order statistics, the CDF of $X_{k:n}$ is given as
$$ P[X_{k:n} leq x] = sum_{j=k}^n {n choose j} (F(x))^j(1-F(x))^{n-j}$$



From CDF, the PMF can be derived as:
$$P[X_{k:n} = x] = P[X_{k:n} leq x] - P[X_{k:n} leq x-1] $$



and the expectation :
$$E[X_{k:n}] = sum_{x = k}^infty x P[X_{k:n} = x]$$



I fear the direct calculation in such manner would involve complex algebra. Is there any simple way to derive such expectation. I also read the "The Order Statistics of the Negative Binomial Distribution" by D. H. Young (link to the paper - The Order Statistics of the Negative Binomial Distribution). Although, the author uses the recurrence relation to calculate m-th moments.



Any help in this matter, even a simple algebra trick would be much appreciated.










share|cite|improve this question









$endgroup$

















    0












    $begingroup$


    Let $ X_1, X_2,...$ be i.i.d $NB(k,q)$. I am interested in calculating the expectation of their k-th order statistic $X_{k:n}$. From my understanding of order statistics, the CDF of $X_{k:n}$ is given as
    $$ P[X_{k:n} leq x] = sum_{j=k}^n {n choose j} (F(x))^j(1-F(x))^{n-j}$$



    From CDF, the PMF can be derived as:
    $$P[X_{k:n} = x] = P[X_{k:n} leq x] - P[X_{k:n} leq x-1] $$



    and the expectation :
    $$E[X_{k:n}] = sum_{x = k}^infty x P[X_{k:n} = x]$$



    I fear the direct calculation in such manner would involve complex algebra. Is there any simple way to derive such expectation. I also read the "The Order Statistics of the Negative Binomial Distribution" by D. H. Young (link to the paper - The Order Statistics of the Negative Binomial Distribution). Although, the author uses the recurrence relation to calculate m-th moments.



    Any help in this matter, even a simple algebra trick would be much appreciated.










    share|cite|improve this question









    $endgroup$















      0












      0








      0


      1



      $begingroup$


      Let $ X_1, X_2,...$ be i.i.d $NB(k,q)$. I am interested in calculating the expectation of their k-th order statistic $X_{k:n}$. From my understanding of order statistics, the CDF of $X_{k:n}$ is given as
      $$ P[X_{k:n} leq x] = sum_{j=k}^n {n choose j} (F(x))^j(1-F(x))^{n-j}$$



      From CDF, the PMF can be derived as:
      $$P[X_{k:n} = x] = P[X_{k:n} leq x] - P[X_{k:n} leq x-1] $$



      and the expectation :
      $$E[X_{k:n}] = sum_{x = k}^infty x P[X_{k:n} = x]$$



      I fear the direct calculation in such manner would involve complex algebra. Is there any simple way to derive such expectation. I also read the "The Order Statistics of the Negative Binomial Distribution" by D. H. Young (link to the paper - The Order Statistics of the Negative Binomial Distribution). Although, the author uses the recurrence relation to calculate m-th moments.



      Any help in this matter, even a simple algebra trick would be much appreciated.










      share|cite|improve this question









      $endgroup$




      Let $ X_1, X_2,...$ be i.i.d $NB(k,q)$. I am interested in calculating the expectation of their k-th order statistic $X_{k:n}$. From my understanding of order statistics, the CDF of $X_{k:n}$ is given as
      $$ P[X_{k:n} leq x] = sum_{j=k}^n {n choose j} (F(x))^j(1-F(x))^{n-j}$$



      From CDF, the PMF can be derived as:
      $$P[X_{k:n} = x] = P[X_{k:n} leq x] - P[X_{k:n} leq x-1] $$



      and the expectation :
      $$E[X_{k:n}] = sum_{x = k}^infty x P[X_{k:n} = x]$$



      I fear the direct calculation in such manner would involve complex algebra. Is there any simple way to derive such expectation. I also read the "The Order Statistics of the Negative Binomial Distribution" by D. H. Young (link to the paper - The Order Statistics of the Negative Binomial Distribution). Although, the author uses the recurrence relation to calculate m-th moments.



      Any help in this matter, even a simple algebra trick would be much appreciated.







      order-statistics negative-binomial






      share|cite|improve this question













      share|cite|improve this question











      share|cite|improve this question




      share|cite|improve this question










      asked Dec 3 '18 at 0:21









      Resting PlatypusResting Platypus

      12




      12






















          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%2f3023422%2fexpectation-of-k-th-order-statistic-of-negative-binomial-distribution%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%2f3023422%2fexpectation-of-k-th-order-statistic-of-negative-binomial-distribution%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

          Bundesstraße 106

          Verónica Boquete

          Ida-Boy-Ed-Garten