Complete statistics












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$begingroup$


Let $(x_{1}, ldots, x_{n})$ be a sample from some known distribution $F_{theta}$ with unknown parameter $theta$ and let $$mathbb{E}_{theta}{X_{i}} = theta$$
Let $T$ be an identity function of a sample e.g. for the given sample $T$ returns the sample itself. How to prove that $T$ is not a complete statistics?



By definition, the complete statistics is a function $T$ such that for any measurable $g$ such that $$mathbb{E}(g(T)) = 0$$
for any $theta$
$$mathbb{P}_{theta}(g(T) = 0) = 1$$
for any $theta$.



I guess that the problem is quite easy but i cannot find an easy way to attack it. Are there any hints that might help?










share|cite|improve this question









$endgroup$

















    1












    $begingroup$


    Let $(x_{1}, ldots, x_{n})$ be a sample from some known distribution $F_{theta}$ with unknown parameter $theta$ and let $$mathbb{E}_{theta}{X_{i}} = theta$$
    Let $T$ be an identity function of a sample e.g. for the given sample $T$ returns the sample itself. How to prove that $T$ is not a complete statistics?



    By definition, the complete statistics is a function $T$ such that for any measurable $g$ such that $$mathbb{E}(g(T)) = 0$$
    for any $theta$
    $$mathbb{P}_{theta}(g(T) = 0) = 1$$
    for any $theta$.



    I guess that the problem is quite easy but i cannot find an easy way to attack it. Are there any hints that might help?










    share|cite|improve this question









    $endgroup$















      1












      1








      1


      1



      $begingroup$


      Let $(x_{1}, ldots, x_{n})$ be a sample from some known distribution $F_{theta}$ with unknown parameter $theta$ and let $$mathbb{E}_{theta}{X_{i}} = theta$$
      Let $T$ be an identity function of a sample e.g. for the given sample $T$ returns the sample itself. How to prove that $T$ is not a complete statistics?



      By definition, the complete statistics is a function $T$ such that for any measurable $g$ such that $$mathbb{E}(g(T)) = 0$$
      for any $theta$
      $$mathbb{P}_{theta}(g(T) = 0) = 1$$
      for any $theta$.



      I guess that the problem is quite easy but i cannot find an easy way to attack it. Are there any hints that might help?










      share|cite|improve this question









      $endgroup$




      Let $(x_{1}, ldots, x_{n})$ be a sample from some known distribution $F_{theta}$ with unknown parameter $theta$ and let $$mathbb{E}_{theta}{X_{i}} = theta$$
      Let $T$ be an identity function of a sample e.g. for the given sample $T$ returns the sample itself. How to prove that $T$ is not a complete statistics?



      By definition, the complete statistics is a function $T$ such that for any measurable $g$ such that $$mathbb{E}(g(T)) = 0$$
      for any $theta$
      $$mathbb{P}_{theta}(g(T) = 0) = 1$$
      for any $theta$.



      I guess that the problem is quite easy but i cannot find an easy way to attack it. Are there any hints that might help?







      statistics statistical-inference






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      asked Dec 17 '18 at 18:51









      hyperkahlerhyperkahler

      1,471714




      1,471714






















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          $begingroup$

          Take $g(T)=X_1-X_2$. Then $E(g(T))=0$ but $g$ is not identically $0$ with probability $1$.






          share|cite|improve this answer









          $endgroup$













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            active

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            1












            $begingroup$

            Take $g(T)=X_1-X_2$. Then $E(g(T))=0$ but $g$ is not identically $0$ with probability $1$.






            share|cite|improve this answer









            $endgroup$


















              1












              $begingroup$

              Take $g(T)=X_1-X_2$. Then $E(g(T))=0$ but $g$ is not identically $0$ with probability $1$.






              share|cite|improve this answer









              $endgroup$
















                1












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                1





                $begingroup$

                Take $g(T)=X_1-X_2$. Then $E(g(T))=0$ but $g$ is not identically $0$ with probability $1$.






                share|cite|improve this answer









                $endgroup$



                Take $g(T)=X_1-X_2$. Then $E(g(T))=0$ but $g$ is not identically $0$ with probability $1$.







                share|cite|improve this answer












                share|cite|improve this answer



                share|cite|improve this answer










                answered Dec 17 '18 at 18:58









                pulpfictionalpulpfictional

                835




                835






























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