Deduce X from a constant in variance properties

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How do you consider $operatornameVar(c-alpha X)$?



I'm learning that $V(c) = 0$, where $c$ is a constant.



Does it turn the above into:



$0 - operatornameVar(alpha X) = -[alpha^2operatornameVar(X)]$










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    up vote
    0
    down vote

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    How do you consider $operatornameVar(c-alpha X)$?



    I'm learning that $V(c) = 0$, where $c$ is a constant.



    Does it turn the above into:



    $0 - operatornameVar(alpha X) = -[alpha^2operatornameVar(X)]$










    share|cite|improve this question

























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      How do you consider $operatornameVar(c-alpha X)$?



      I'm learning that $V(c) = 0$, where $c$ is a constant.



      Does it turn the above into:



      $0 - operatornameVar(alpha X) = -[alpha^2operatornameVar(X)]$










      share|cite|improve this question















      How do you consider $operatornameVar(c-alpha X)$?



      I'm learning that $V(c) = 0$, where $c$ is a constant.



      Does it turn the above into:



      $0 - operatornameVar(alpha X) = -[alpha^2operatornameVar(X)]$







      statistics variance






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      share|cite|improve this question













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      edited Sep 7 at 8:54









      Bernard

      112k635104




      112k635104










      asked Sep 7 at 8:02









      Shimmy

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      1368




















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          beginalign
          Var(c-aX) &= Var(-aX) \
          &= (-a)^2Var(X)
          endalign



          We have $$Var(aX+bY) = a^2Var(X)+b^2Var(Y) + 2abCov(X,Y)$$






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          • Thank you very much!
            – Shimmy
            Sep 7 at 8:04










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          1 Answer
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          active

          oldest

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          1 Answer
          1






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          active

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          up vote
          2
          down vote



          accepted










          beginalign
          Var(c-aX) &= Var(-aX) \
          &= (-a)^2Var(X)
          endalign



          We have $$Var(aX+bY) = a^2Var(X)+b^2Var(Y) + 2abCov(X,Y)$$






          share|cite|improve this answer






















          • Thank you very much!
            – Shimmy
            Sep 7 at 8:04














          up vote
          2
          down vote



          accepted










          beginalign
          Var(c-aX) &= Var(-aX) \
          &= (-a)^2Var(X)
          endalign



          We have $$Var(aX+bY) = a^2Var(X)+b^2Var(Y) + 2abCov(X,Y)$$






          share|cite|improve this answer






















          • Thank you very much!
            – Shimmy
            Sep 7 at 8:04












          up vote
          2
          down vote



          accepted







          up vote
          2
          down vote



          accepted






          beginalign
          Var(c-aX) &= Var(-aX) \
          &= (-a)^2Var(X)
          endalign



          We have $$Var(aX+bY) = a^2Var(X)+b^2Var(Y) + 2abCov(X,Y)$$






          share|cite|improve this answer














          beginalign
          Var(c-aX) &= Var(-aX) \
          &= (-a)^2Var(X)
          endalign



          We have $$Var(aX+bY) = a^2Var(X)+b^2Var(Y) + 2abCov(X,Y)$$







          share|cite|improve this answer














          share|cite|improve this answer



          share|cite|improve this answer








          edited Sep 7 at 8:05

























          answered Sep 7 at 8:04









          Siong Thye Goh

          82.7k1456104




          82.7k1456104











          • Thank you very much!
            – Shimmy
            Sep 7 at 8:04
















          • Thank you very much!
            – Shimmy
            Sep 7 at 8:04















          Thank you very much!
          – Shimmy
          Sep 7 at 8:04




          Thank you very much!
          – Shimmy
          Sep 7 at 8:04

















           

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