probability re: comparing 2 iid exponential random variables












0












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Let $X, Y$ be iid exponential random variables with parameter $1$. Then, what is the probability that $X < Y + 1$?



I know how to compute $P(X < Y)$ (from integrating the joint PDF, which is the same as the product of the marginal PDFs for X and Y because X and Y are independent, and the marginal PDF is the PDF of an exponential random variable with parameter $1$).



Maybe I'm missing something obvious, but the $+ 1$ is really tripping me up.










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    0












    $begingroup$


    Let $X, Y$ be iid exponential random variables with parameter $1$. Then, what is the probability that $X < Y + 1$?



    I know how to compute $P(X < Y)$ (from integrating the joint PDF, which is the same as the product of the marginal PDFs for X and Y because X and Y are independent, and the marginal PDF is the PDF of an exponential random variable with parameter $1$).



    Maybe I'm missing something obvious, but the $+ 1$ is really tripping me up.










    share|cite|improve this question









    $endgroup$















      0












      0








      0





      $begingroup$


      Let $X, Y$ be iid exponential random variables with parameter $1$. Then, what is the probability that $X < Y + 1$?



      I know how to compute $P(X < Y)$ (from integrating the joint PDF, which is the same as the product of the marginal PDFs for X and Y because X and Y are independent, and the marginal PDF is the PDF of an exponential random variable with parameter $1$).



      Maybe I'm missing something obvious, but the $+ 1$ is really tripping me up.










      share|cite|improve this question









      $endgroup$




      Let $X, Y$ be iid exponential random variables with parameter $1$. Then, what is the probability that $X < Y + 1$?



      I know how to compute $P(X < Y)$ (from integrating the joint PDF, which is the same as the product of the marginal PDFs for X and Y because X and Y are independent, and the marginal PDF is the PDF of an exponential random variable with parameter $1$).



      Maybe I'm missing something obvious, but the $+ 1$ is really tripping me up.







      probability probability-distributions exponential-distribution






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      asked Dec 9 '18 at 17:18









      0k330k33

      12010




      12010






















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          Given that you know how to integrate the joint density, then all you have to do is modify the region of integration suitably: The inequality $X < Y + 1$ with the added conditions $X > 0$, $Y > 0$, would represent what region of the $(X,Y)$ coordinate plane? Plot the equation $Y = X - 1$. What does that look like? Now, sketch the region satisfying the inequalities. Then consider how to set up an iterated integral over which you would integrate the joint density: one order of integration will be more inconvenient than the other, so choose carefully.






          share|cite|improve this answer









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          • $begingroup$
            Thank you! For some reason I thought the distribution itself would change, not just the integration limits.
            $endgroup$
            – 0k33
            Dec 9 '18 at 19:09











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          $begingroup$

          Given that you know how to integrate the joint density, then all you have to do is modify the region of integration suitably: The inequality $X < Y + 1$ with the added conditions $X > 0$, $Y > 0$, would represent what region of the $(X,Y)$ coordinate plane? Plot the equation $Y = X - 1$. What does that look like? Now, sketch the region satisfying the inequalities. Then consider how to set up an iterated integral over which you would integrate the joint density: one order of integration will be more inconvenient than the other, so choose carefully.






          share|cite|improve this answer









          $endgroup$













          • $begingroup$
            Thank you! For some reason I thought the distribution itself would change, not just the integration limits.
            $endgroup$
            – 0k33
            Dec 9 '18 at 19:09
















          1












          $begingroup$

          Given that you know how to integrate the joint density, then all you have to do is modify the region of integration suitably: The inequality $X < Y + 1$ with the added conditions $X > 0$, $Y > 0$, would represent what region of the $(X,Y)$ coordinate plane? Plot the equation $Y = X - 1$. What does that look like? Now, sketch the region satisfying the inequalities. Then consider how to set up an iterated integral over which you would integrate the joint density: one order of integration will be more inconvenient than the other, so choose carefully.






          share|cite|improve this answer









          $endgroup$













          • $begingroup$
            Thank you! For some reason I thought the distribution itself would change, not just the integration limits.
            $endgroup$
            – 0k33
            Dec 9 '18 at 19:09














          1












          1








          1





          $begingroup$

          Given that you know how to integrate the joint density, then all you have to do is modify the region of integration suitably: The inequality $X < Y + 1$ with the added conditions $X > 0$, $Y > 0$, would represent what region of the $(X,Y)$ coordinate plane? Plot the equation $Y = X - 1$. What does that look like? Now, sketch the region satisfying the inequalities. Then consider how to set up an iterated integral over which you would integrate the joint density: one order of integration will be more inconvenient than the other, so choose carefully.






          share|cite|improve this answer









          $endgroup$



          Given that you know how to integrate the joint density, then all you have to do is modify the region of integration suitably: The inequality $X < Y + 1$ with the added conditions $X > 0$, $Y > 0$, would represent what region of the $(X,Y)$ coordinate plane? Plot the equation $Y = X - 1$. What does that look like? Now, sketch the region satisfying the inequalities. Then consider how to set up an iterated integral over which you would integrate the joint density: one order of integration will be more inconvenient than the other, so choose carefully.







          share|cite|improve this answer












          share|cite|improve this answer



          share|cite|improve this answer










          answered Dec 9 '18 at 17:27









          heropupheropup

          63k66199




          63k66199












          • $begingroup$
            Thank you! For some reason I thought the distribution itself would change, not just the integration limits.
            $endgroup$
            – 0k33
            Dec 9 '18 at 19:09


















          • $begingroup$
            Thank you! For some reason I thought the distribution itself would change, not just the integration limits.
            $endgroup$
            – 0k33
            Dec 9 '18 at 19:09
















          $begingroup$
          Thank you! For some reason I thought the distribution itself would change, not just the integration limits.
          $endgroup$
          – 0k33
          Dec 9 '18 at 19:09




          $begingroup$
          Thank you! For some reason I thought the distribution itself would change, not just the integration limits.
          $endgroup$
          – 0k33
          Dec 9 '18 at 19:09


















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