For a general linear regression , are Y and Y hat independent?












0












$begingroup$


For a general linear regression , are $Y$ and $hat{Y}$ independent?



$Y$=XB+e



$hat{Y}$=X$hat{B}$



I think they are dependent, because if they rely on the same data, they should have some sort of relationship.



that is to say , $hat{Y}$=HY , so they are dependent right?










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$endgroup$












  • $begingroup$
    "...because if they rely on the same data..." Could you explain what you mean by that?
    $endgroup$
    – daOnlyBG
    Nov 6 '14 at 21:09










  • $begingroup$
    well, isn't Y= xb +e , and Y hat = xBhat . they all rely on x and y data?
    $endgroup$
    – user1919987
    Nov 6 '14 at 21:20










  • $begingroup$
    Perhaps define $Y$ and $hat{Y}$.
    $endgroup$
    – parsiad
    Nov 6 '14 at 21:28
















0












$begingroup$


For a general linear regression , are $Y$ and $hat{Y}$ independent?



$Y$=XB+e



$hat{Y}$=X$hat{B}$



I think they are dependent, because if they rely on the same data, they should have some sort of relationship.



that is to say , $hat{Y}$=HY , so they are dependent right?










share|cite|improve this question











$endgroup$












  • $begingroup$
    "...because if they rely on the same data..." Could you explain what you mean by that?
    $endgroup$
    – daOnlyBG
    Nov 6 '14 at 21:09










  • $begingroup$
    well, isn't Y= xb +e , and Y hat = xBhat . they all rely on x and y data?
    $endgroup$
    – user1919987
    Nov 6 '14 at 21:20










  • $begingroup$
    Perhaps define $Y$ and $hat{Y}$.
    $endgroup$
    – parsiad
    Nov 6 '14 at 21:28














0












0








0





$begingroup$


For a general linear regression , are $Y$ and $hat{Y}$ independent?



$Y$=XB+e



$hat{Y}$=X$hat{B}$



I think they are dependent, because if they rely on the same data, they should have some sort of relationship.



that is to say , $hat{Y}$=HY , so they are dependent right?










share|cite|improve this question











$endgroup$




For a general linear regression , are $Y$ and $hat{Y}$ independent?



$Y$=XB+e



$hat{Y}$=X$hat{B}$



I think they are dependent, because if they rely on the same data, they should have some sort of relationship.



that is to say , $hat{Y}$=HY , so they are dependent right?







regression






share|cite|improve this question















share|cite|improve this question













share|cite|improve this question




share|cite|improve this question








edited Nov 6 '14 at 21:51







user1919987

















asked Nov 6 '14 at 21:06









user1919987user1919987

621414




621414












  • $begingroup$
    "...because if they rely on the same data..." Could you explain what you mean by that?
    $endgroup$
    – daOnlyBG
    Nov 6 '14 at 21:09










  • $begingroup$
    well, isn't Y= xb +e , and Y hat = xBhat . they all rely on x and y data?
    $endgroup$
    – user1919987
    Nov 6 '14 at 21:20










  • $begingroup$
    Perhaps define $Y$ and $hat{Y}$.
    $endgroup$
    – parsiad
    Nov 6 '14 at 21:28


















  • $begingroup$
    "...because if they rely on the same data..." Could you explain what you mean by that?
    $endgroup$
    – daOnlyBG
    Nov 6 '14 at 21:09










  • $begingroup$
    well, isn't Y= xb +e , and Y hat = xBhat . they all rely on x and y data?
    $endgroup$
    – user1919987
    Nov 6 '14 at 21:20










  • $begingroup$
    Perhaps define $Y$ and $hat{Y}$.
    $endgroup$
    – parsiad
    Nov 6 '14 at 21:28
















$begingroup$
"...because if they rely on the same data..." Could you explain what you mean by that?
$endgroup$
– daOnlyBG
Nov 6 '14 at 21:09




$begingroup$
"...because if they rely on the same data..." Could you explain what you mean by that?
$endgroup$
– daOnlyBG
Nov 6 '14 at 21:09












$begingroup$
well, isn't Y= xb +e , and Y hat = xBhat . they all rely on x and y data?
$endgroup$
– user1919987
Nov 6 '14 at 21:20




$begingroup$
well, isn't Y= xb +e , and Y hat = xBhat . they all rely on x and y data?
$endgroup$
– user1919987
Nov 6 '14 at 21:20












$begingroup$
Perhaps define $Y$ and $hat{Y}$.
$endgroup$
– parsiad
Nov 6 '14 at 21:28




$begingroup$
Perhaps define $Y$ and $hat{Y}$.
$endgroup$
– parsiad
Nov 6 '14 at 21:28










1 Answer
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$begingroup$

As long as B is not equal to 0, the answer is no. If B is not 0, then both terms will depend on X and so they cannot be independent.



$Cov(Y,hat{Y})=Cov(XB+e,Ŷ) = B*cov(X,Xhat{b})$



Edit: I suppose if your model is misspecified, you could get an incorrect estimate of $hat{b}=0$, and thus no correlation, but I don't think thats what you had in mind.






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    1 Answer
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    active

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    1 Answer
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    0












    $begingroup$

    As long as B is not equal to 0, the answer is no. If B is not 0, then both terms will depend on X and so they cannot be independent.



    $Cov(Y,hat{Y})=Cov(XB+e,Ŷ) = B*cov(X,Xhat{b})$



    Edit: I suppose if your model is misspecified, you could get an incorrect estimate of $hat{b}=0$, and thus no correlation, but I don't think thats what you had in mind.






    share|cite|improve this answer









    $endgroup$


















      0












      $begingroup$

      As long as B is not equal to 0, the answer is no. If B is not 0, then both terms will depend on X and so they cannot be independent.



      $Cov(Y,hat{Y})=Cov(XB+e,Ŷ) = B*cov(X,Xhat{b})$



      Edit: I suppose if your model is misspecified, you could get an incorrect estimate of $hat{b}=0$, and thus no correlation, but I don't think thats what you had in mind.






      share|cite|improve this answer









      $endgroup$
















        0












        0








        0





        $begingroup$

        As long as B is not equal to 0, the answer is no. If B is not 0, then both terms will depend on X and so they cannot be independent.



        $Cov(Y,hat{Y})=Cov(XB+e,Ŷ) = B*cov(X,Xhat{b})$



        Edit: I suppose if your model is misspecified, you could get an incorrect estimate of $hat{b}=0$, and thus no correlation, but I don't think thats what you had in mind.






        share|cite|improve this answer









        $endgroup$



        As long as B is not equal to 0, the answer is no. If B is not 0, then both terms will depend on X and so they cannot be independent.



        $Cov(Y,hat{Y})=Cov(XB+e,Ŷ) = B*cov(X,Xhat{b})$



        Edit: I suppose if your model is misspecified, you could get an incorrect estimate of $hat{b}=0$, and thus no correlation, but I don't think thats what you had in mind.







        share|cite|improve this answer












        share|cite|improve this answer



        share|cite|improve this answer










        answered Nov 7 '14 at 23:01









        GregGreg

        527311




        527311






























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