For what value of $c$, we have $bar{theta}$ is unbiased?











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Given a population with the density function
$$f(x)=frac{2(theta-x)}{theta^2}$$ for $0<x<theta$, consider the estimator of $theta$ of the form $bar{theta}=cbar{x}$ where $c$ is constant.
For what value of $c$, do we have that $bar{theta}$ is unbiased?




My attempt:



By definition, a estimator is unbiased if $E[bar{theta}]=theta$



But here i'm a little confused because i have a density function. Can someone help me?










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    up vote
    0
    down vote

    favorite













    Given a population with the density function
    $$f(x)=frac{2(theta-x)}{theta^2}$$ for $0<x<theta$, consider the estimator of $theta$ of the form $bar{theta}=cbar{x}$ where $c$ is constant.
    For what value of $c$, do we have that $bar{theta}$ is unbiased?




    My attempt:



    By definition, a estimator is unbiased if $E[bar{theta}]=theta$



    But here i'm a little confused because i have a density function. Can someone help me?










    share|cite|improve this question


























      up vote
      0
      down vote

      favorite









      up vote
      0
      down vote

      favorite












      Given a population with the density function
      $$f(x)=frac{2(theta-x)}{theta^2}$$ for $0<x<theta$, consider the estimator of $theta$ of the form $bar{theta}=cbar{x}$ where $c$ is constant.
      For what value of $c$, do we have that $bar{theta}$ is unbiased?




      My attempt:



      By definition, a estimator is unbiased if $E[bar{theta}]=theta$



      But here i'm a little confused because i have a density function. Can someone help me?










      share|cite|improve this question
















      Given a population with the density function
      $$f(x)=frac{2(theta-x)}{theta^2}$$ for $0<x<theta$, consider the estimator of $theta$ of the form $bar{theta}=cbar{x}$ where $c$ is constant.
      For what value of $c$, do we have that $bar{theta}$ is unbiased?




      My attempt:



      By definition, a estimator is unbiased if $E[bar{theta}]=theta$



      But here i'm a little confused because i have a density function. Can someone help me?







      probability






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      edited Nov 25 at 21:56









      Clement C.

      49.1k33785




      49.1k33785










      asked Nov 25 at 21:43









      Bvss12

      1,729617




      1,729617






















          1 Answer
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          This may get you started:
          $$E[bartheta]=E[cbar X]=cE[bar X]=frac{c}{n}sum_{i=1}^nE[X_i]$$
          Then using the density function, you can find the expected value inside the sum.






          share|cite|improve this answer

















          • 1




            Thanks for all!
            – Bvss12
            Nov 25 at 22:17











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          1 Answer
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          active

          oldest

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          1 Answer
          1






          active

          oldest

          votes









          active

          oldest

          votes






          active

          oldest

          votes








          up vote
          1
          down vote



          accepted










          This may get you started:
          $$E[bartheta]=E[cbar X]=cE[bar X]=frac{c}{n}sum_{i=1}^nE[X_i]$$
          Then using the density function, you can find the expected value inside the sum.






          share|cite|improve this answer

















          • 1




            Thanks for all!
            – Bvss12
            Nov 25 at 22:17















          up vote
          1
          down vote



          accepted










          This may get you started:
          $$E[bartheta]=E[cbar X]=cE[bar X]=frac{c}{n}sum_{i=1}^nE[X_i]$$
          Then using the density function, you can find the expected value inside the sum.






          share|cite|improve this answer

















          • 1




            Thanks for all!
            – Bvss12
            Nov 25 at 22:17













          up vote
          1
          down vote



          accepted







          up vote
          1
          down vote



          accepted






          This may get you started:
          $$E[bartheta]=E[cbar X]=cE[bar X]=frac{c}{n}sum_{i=1}^nE[X_i]$$
          Then using the density function, you can find the expected value inside the sum.






          share|cite|improve this answer












          This may get you started:
          $$E[bartheta]=E[cbar X]=cE[bar X]=frac{c}{n}sum_{i=1}^nE[X_i]$$
          Then using the density function, you can find the expected value inside the sum.







          share|cite|improve this answer












          share|cite|improve this answer



          share|cite|improve this answer










          answered Nov 25 at 21:50









          gd1035

          461210




          461210








          • 1




            Thanks for all!
            – Bvss12
            Nov 25 at 22:17














          • 1




            Thanks for all!
            – Bvss12
            Nov 25 at 22:17








          1




          1




          Thanks for all!
          – Bvss12
          Nov 25 at 22:17




          Thanks for all!
          – Bvss12
          Nov 25 at 22:17


















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