Upper bound probability of variable that decreases at every step











up vote
0
down vote

favorite












I'm having a hard time wrapping my mind around this small probability problem.



We start with a variable $X$, that has some fixed integer value in $[d,n]$. At each step, there is a $frac{X}{n}$ chance that we decrease the value of $X$ by 1. We repeat this $m$ times.



What is an upper bound on the probability that the value of $X$ is $geq d$ at the end of this?










share|cite|improve this question


























    up vote
    0
    down vote

    favorite












    I'm having a hard time wrapping my mind around this small probability problem.



    We start with a variable $X$, that has some fixed integer value in $[d,n]$. At each step, there is a $frac{X}{n}$ chance that we decrease the value of $X$ by 1. We repeat this $m$ times.



    What is an upper bound on the probability that the value of $X$ is $geq d$ at the end of this?










    share|cite|improve this question
























      up vote
      0
      down vote

      favorite









      up vote
      0
      down vote

      favorite











      I'm having a hard time wrapping my mind around this small probability problem.



      We start with a variable $X$, that has some fixed integer value in $[d,n]$. At each step, there is a $frac{X}{n}$ chance that we decrease the value of $X$ by 1. We repeat this $m$ times.



      What is an upper bound on the probability that the value of $X$ is $geq d$ at the end of this?










      share|cite|improve this question













      I'm having a hard time wrapping my mind around this small probability problem.



      We start with a variable $X$, that has some fixed integer value in $[d,n]$. At each step, there is a $frac{X}{n}$ chance that we decrease the value of $X$ by 1. We repeat this $m$ times.



      What is an upper bound on the probability that the value of $X$ is $geq d$ at the end of this?







      probability






      share|cite|improve this question













      share|cite|improve this question











      share|cite|improve this question




      share|cite|improve this question










      asked Nov 15 at 3:07









      Claire Chen

      133




      133



























          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',
          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%2f2999151%2fupper-bound-probability-of-variable-that-decreases-at-every-step%23new-answer', 'question_page');
          }
          );

          Post as a guest















          Required, but never shown






























          active

          oldest

          votes













          active

          oldest

          votes









          active

          oldest

          votes






          active

          oldest

          votes
















           

          draft saved


          draft discarded



















































           


          draft saved


          draft discarded














          StackExchange.ready(
          function () {
          StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f2999151%2fupper-bound-probability-of-variable-that-decreases-at-every-step%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

          How to change which sound is reproduced for terminal bell?

          Title Spacing in Bjornstrup Chapter, Removing Chapter Number From Contents

          Can I use Tabulator js library in my java Spring + Thymeleaf project?