Sequence of random variables and convergence in probability.












0












$begingroup$


Let $Omega:=[0,1]$ with Lebesgue measure.Let's define a sequence $X_n= frac{omega}{n}$.
Check:



a) Convergence in distribution



b) Convergence in probability



My solution:
b)
$P(|X_n-X| ge epsilon)=P(|X_n| ge epsilon)=P(frac{omega}{n} ge epsilon)=P(omega ge epsilon n )$
And this is equal 0 for each $epsilon >0$ and $ n to infty$.



a)
$X equiv 0$



We have $F_X(t)= begin{cases} 0 &text{for } t < 0\1 &text{for } t ge 0end{cases}$



Now we have to calculate $F_{X_n}$ and here I have problem.










share|cite|improve this question









$endgroup$

















    0












    $begingroup$


    Let $Omega:=[0,1]$ with Lebesgue measure.Let's define a sequence $X_n= frac{omega}{n}$.
    Check:



    a) Convergence in distribution



    b) Convergence in probability



    My solution:
    b)
    $P(|X_n-X| ge epsilon)=P(|X_n| ge epsilon)=P(frac{omega}{n} ge epsilon)=P(omega ge epsilon n )$
    And this is equal 0 for each $epsilon >0$ and $ n to infty$.



    a)
    $X equiv 0$



    We have $F_X(t)= begin{cases} 0 &text{for } t < 0\1 &text{for } t ge 0end{cases}$



    Now we have to calculate $F_{X_n}$ and here I have problem.










    share|cite|improve this question









    $endgroup$















      0












      0








      0





      $begingroup$


      Let $Omega:=[0,1]$ with Lebesgue measure.Let's define a sequence $X_n= frac{omega}{n}$.
      Check:



      a) Convergence in distribution



      b) Convergence in probability



      My solution:
      b)
      $P(|X_n-X| ge epsilon)=P(|X_n| ge epsilon)=P(frac{omega}{n} ge epsilon)=P(omega ge epsilon n )$
      And this is equal 0 for each $epsilon >0$ and $ n to infty$.



      a)
      $X equiv 0$



      We have $F_X(t)= begin{cases} 0 &text{for } t < 0\1 &text{for } t ge 0end{cases}$



      Now we have to calculate $F_{X_n}$ and here I have problem.










      share|cite|improve this question









      $endgroup$




      Let $Omega:=[0,1]$ with Lebesgue measure.Let's define a sequence $X_n= frac{omega}{n}$.
      Check:



      a) Convergence in distribution



      b) Convergence in probability



      My solution:
      b)
      $P(|X_n-X| ge epsilon)=P(|X_n| ge epsilon)=P(frac{omega}{n} ge epsilon)=P(omega ge epsilon n )$
      And this is equal 0 for each $epsilon >0$ and $ n to infty$.



      a)
      $X equiv 0$



      We have $F_X(t)= begin{cases} 0 &text{for } t < 0\1 &text{for } t ge 0end{cases}$



      Now we have to calculate $F_{X_n}$ and here I have problem.







      probability convergence random-variables






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      asked Jan 17 at 16:36









      pawelKpawelK

      618




      618






















          1 Answer
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          0












          $begingroup$

          Convergence in probability implies convergence in distribution, so having done b) you do not need to do a).






          share|cite|improve this answer









          $endgroup$













          • $begingroup$
            Ok, but I have problem with a.
            $endgroup$
            – pawelK
            Jan 17 at 19:06










          • $begingroup$
            You shouldn't have, as you did b) and b) => a). But ok, if you want to do it without using b), then you can see that F_X_n(t) = 0 for t<0, 1 for t>1/n, and it is linear on [0,1/n], so nt for t in [0,1/n].
            $endgroup$
            – Jakub Andruszkiewicz
            Jan 17 at 19:12












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          1 Answer
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          1 Answer
          1






          active

          oldest

          votes









          active

          oldest

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          active

          oldest

          votes









          0












          $begingroup$

          Convergence in probability implies convergence in distribution, so having done b) you do not need to do a).






          share|cite|improve this answer









          $endgroup$













          • $begingroup$
            Ok, but I have problem with a.
            $endgroup$
            – pawelK
            Jan 17 at 19:06










          • $begingroup$
            You shouldn't have, as you did b) and b) => a). But ok, if you want to do it without using b), then you can see that F_X_n(t) = 0 for t<0, 1 for t>1/n, and it is linear on [0,1/n], so nt for t in [0,1/n].
            $endgroup$
            – Jakub Andruszkiewicz
            Jan 17 at 19:12
















          0












          $begingroup$

          Convergence in probability implies convergence in distribution, so having done b) you do not need to do a).






          share|cite|improve this answer









          $endgroup$













          • $begingroup$
            Ok, but I have problem with a.
            $endgroup$
            – pawelK
            Jan 17 at 19:06










          • $begingroup$
            You shouldn't have, as you did b) and b) => a). But ok, if you want to do it without using b), then you can see that F_X_n(t) = 0 for t<0, 1 for t>1/n, and it is linear on [0,1/n], so nt for t in [0,1/n].
            $endgroup$
            – Jakub Andruszkiewicz
            Jan 17 at 19:12














          0












          0








          0





          $begingroup$

          Convergence in probability implies convergence in distribution, so having done b) you do not need to do a).






          share|cite|improve this answer









          $endgroup$



          Convergence in probability implies convergence in distribution, so having done b) you do not need to do a).







          share|cite|improve this answer












          share|cite|improve this answer



          share|cite|improve this answer










          answered Jan 17 at 18:59









          Jakub AndruszkiewiczJakub Andruszkiewicz

          2116




          2116












          • $begingroup$
            Ok, but I have problem with a.
            $endgroup$
            – pawelK
            Jan 17 at 19:06










          • $begingroup$
            You shouldn't have, as you did b) and b) => a). But ok, if you want to do it without using b), then you can see that F_X_n(t) = 0 for t<0, 1 for t>1/n, and it is linear on [0,1/n], so nt for t in [0,1/n].
            $endgroup$
            – Jakub Andruszkiewicz
            Jan 17 at 19:12


















          • $begingroup$
            Ok, but I have problem with a.
            $endgroup$
            – pawelK
            Jan 17 at 19:06










          • $begingroup$
            You shouldn't have, as you did b) and b) => a). But ok, if you want to do it without using b), then you can see that F_X_n(t) = 0 for t<0, 1 for t>1/n, and it is linear on [0,1/n], so nt for t in [0,1/n].
            $endgroup$
            – Jakub Andruszkiewicz
            Jan 17 at 19:12
















          $begingroup$
          Ok, but I have problem with a.
          $endgroup$
          – pawelK
          Jan 17 at 19:06




          $begingroup$
          Ok, but I have problem with a.
          $endgroup$
          – pawelK
          Jan 17 at 19:06












          $begingroup$
          You shouldn't have, as you did b) and b) => a). But ok, if you want to do it without using b), then you can see that F_X_n(t) = 0 for t<0, 1 for t>1/n, and it is linear on [0,1/n], so nt for t in [0,1/n].
          $endgroup$
          – Jakub Andruszkiewicz
          Jan 17 at 19:12




          $begingroup$
          You shouldn't have, as you did b) and b) => a). But ok, if you want to do it without using b), then you can see that F_X_n(t) = 0 for t<0, 1 for t>1/n, and it is linear on [0,1/n], so nt for t in [0,1/n].
          $endgroup$
          – Jakub Andruszkiewicz
          Jan 17 at 19:12


















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