Transformation of Random variable $Y=-2ln(F(x))$ [on hold]












-1














Let $X$ is a continuous Random variable. with strictly increasing function cumulative distribution function $F(x)$.
Find and recognise the distribution of random variable $Y=-2ln(F(x))$.
I need some help here please.










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put on hold as off-topic by Did, StubbornAtom, Paul Frost, Pierre-Guy Plamondon, Cesareo Jan 4 at 12:50


This question appears to be off-topic. The users who voted to close gave this specific reason:


  • "This question is missing context or other details: Please provide additional context, which ideally explains why the question is relevant to you and our community. Some forms of context include: background and motivation, relevant definitions, source, possible strategies, your current progress, why the question is interesting or important, etc." – Did, StubbornAtom, Paul Frost, Pierre-Guy Plamondon, Cesareo

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  • Can we assume $F$ is continuous?
    – kimchi lover
    Jan 4 at 1:01










  • Yes X is continuous
    – kotsos sgouras
    Jan 4 at 7:22
















-1














Let $X$ is a continuous Random variable. with strictly increasing function cumulative distribution function $F(x)$.
Find and recognise the distribution of random variable $Y=-2ln(F(x))$.
I need some help here please.










share|cite|improve this question















put on hold as off-topic by Did, StubbornAtom, Paul Frost, Pierre-Guy Plamondon, Cesareo Jan 4 at 12:50


This question appears to be off-topic. The users who voted to close gave this specific reason:


  • "This question is missing context or other details: Please provide additional context, which ideally explains why the question is relevant to you and our community. Some forms of context include: background and motivation, relevant definitions, source, possible strategies, your current progress, why the question is interesting or important, etc." – Did, StubbornAtom, Paul Frost, Pierre-Guy Plamondon, Cesareo

If this question can be reworded to fit the rules in the help center, please edit the question.













  • Can we assume $F$ is continuous?
    – kimchi lover
    Jan 4 at 1:01










  • Yes X is continuous
    – kotsos sgouras
    Jan 4 at 7:22














-1












-1








-1







Let $X$ is a continuous Random variable. with strictly increasing function cumulative distribution function $F(x)$.
Find and recognise the distribution of random variable $Y=-2ln(F(x))$.
I need some help here please.










share|cite|improve this question















Let $X$ is a continuous Random variable. with strictly increasing function cumulative distribution function $F(x)$.
Find and recognise the distribution of random variable $Y=-2ln(F(x))$.
I need some help here please.







probability transformation






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share|cite|improve this question













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edited Jan 4 at 7:28

























asked Jan 4 at 0:52









kotsos sgouras

35




35




put on hold as off-topic by Did, StubbornAtom, Paul Frost, Pierre-Guy Plamondon, Cesareo Jan 4 at 12:50


This question appears to be off-topic. The users who voted to close gave this specific reason:


  • "This question is missing context or other details: Please provide additional context, which ideally explains why the question is relevant to you and our community. Some forms of context include: background and motivation, relevant definitions, source, possible strategies, your current progress, why the question is interesting or important, etc." – Did, StubbornAtom, Paul Frost, Pierre-Guy Plamondon, Cesareo

If this question can be reworded to fit the rules in the help center, please edit the question.




put on hold as off-topic by Did, StubbornAtom, Paul Frost, Pierre-Guy Plamondon, Cesareo Jan 4 at 12:50


This question appears to be off-topic. The users who voted to close gave this specific reason:


  • "This question is missing context or other details: Please provide additional context, which ideally explains why the question is relevant to you and our community. Some forms of context include: background and motivation, relevant definitions, source, possible strategies, your current progress, why the question is interesting or important, etc." – Did, StubbornAtom, Paul Frost, Pierre-Guy Plamondon, Cesareo

If this question can be reworded to fit the rules in the help center, please edit the question.












  • Can we assume $F$ is continuous?
    – kimchi lover
    Jan 4 at 1:01










  • Yes X is continuous
    – kotsos sgouras
    Jan 4 at 7:22


















  • Can we assume $F$ is continuous?
    – kimchi lover
    Jan 4 at 1:01










  • Yes X is continuous
    – kotsos sgouras
    Jan 4 at 7:22
















Can we assume $F$ is continuous?
– kimchi lover
Jan 4 at 1:01




Can we assume $F$ is continuous?
– kimchi lover
Jan 4 at 1:01












Yes X is continuous
– kotsos sgouras
Jan 4 at 7:22




Yes X is continuous
– kotsos sgouras
Jan 4 at 7:22










1 Answer
1






active

oldest

votes


















0














It's easy if $F$ is continuous. In that case $P(F(X)leq t)=P(Xleq F^{-1}(t))=F(F^{-1}(t))=t$ for $0<t<1.$ So, $F(X)sim U(0,1).$ $P(-2log F(X)leq y/2)=P(log F(X)geq -y/2)=P(F(X)geq e^{-y/2})=1-e^{-y/2}$ for $y>0.$ So, $Ysim Exp(2)$ or $Ysim chi^2_2.$



But if $F$ is not continuous, i.e, there is jump in $F$, then $F(X)$ might not be uniformly distributed.






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  • We can say $P{Y leq y}=1-F(G(e^{-y/2)}))$ whether or not $F$ is continuous, where $G(t)=inf {x:F(x) geq t}$. If $F$ is continuous then $Fcirc G$ is the identity function.
    – Kavi Rama Murthy
    Jan 4 at 5:56












  • @kotsossgouras The first $y/2$ is a misprint; it should say $y$.
    – J.G.
    Jan 4 at 7:55










  • how we can show that F^-1(F(X))=X ??
    – kotsos sgouras
    Jan 4 at 12:34


















1 Answer
1






active

oldest

votes








1 Answer
1






active

oldest

votes









active

oldest

votes






active

oldest

votes









0














It's easy if $F$ is continuous. In that case $P(F(X)leq t)=P(Xleq F^{-1}(t))=F(F^{-1}(t))=t$ for $0<t<1.$ So, $F(X)sim U(0,1).$ $P(-2log F(X)leq y/2)=P(log F(X)geq -y/2)=P(F(X)geq e^{-y/2})=1-e^{-y/2}$ for $y>0.$ So, $Ysim Exp(2)$ or $Ysim chi^2_2.$



But if $F$ is not continuous, i.e, there is jump in $F$, then $F(X)$ might not be uniformly distributed.






share|cite|improve this answer





















  • We can say $P{Y leq y}=1-F(G(e^{-y/2)}))$ whether or not $F$ is continuous, where $G(t)=inf {x:F(x) geq t}$. If $F$ is continuous then $Fcirc G$ is the identity function.
    – Kavi Rama Murthy
    Jan 4 at 5:56












  • @kotsossgouras The first $y/2$ is a misprint; it should say $y$.
    – J.G.
    Jan 4 at 7:55










  • how we can show that F^-1(F(X))=X ??
    – kotsos sgouras
    Jan 4 at 12:34
















0














It's easy if $F$ is continuous. In that case $P(F(X)leq t)=P(Xleq F^{-1}(t))=F(F^{-1}(t))=t$ for $0<t<1.$ So, $F(X)sim U(0,1).$ $P(-2log F(X)leq y/2)=P(log F(X)geq -y/2)=P(F(X)geq e^{-y/2})=1-e^{-y/2}$ for $y>0.$ So, $Ysim Exp(2)$ or $Ysim chi^2_2.$



But if $F$ is not continuous, i.e, there is jump in $F$, then $F(X)$ might not be uniformly distributed.






share|cite|improve this answer





















  • We can say $P{Y leq y}=1-F(G(e^{-y/2)}))$ whether or not $F$ is continuous, where $G(t)=inf {x:F(x) geq t}$. If $F$ is continuous then $Fcirc G$ is the identity function.
    – Kavi Rama Murthy
    Jan 4 at 5:56












  • @kotsossgouras The first $y/2$ is a misprint; it should say $y$.
    – J.G.
    Jan 4 at 7:55










  • how we can show that F^-1(F(X))=X ??
    – kotsos sgouras
    Jan 4 at 12:34














0












0








0






It's easy if $F$ is continuous. In that case $P(F(X)leq t)=P(Xleq F^{-1}(t))=F(F^{-1}(t))=t$ for $0<t<1.$ So, $F(X)sim U(0,1).$ $P(-2log F(X)leq y/2)=P(log F(X)geq -y/2)=P(F(X)geq e^{-y/2})=1-e^{-y/2}$ for $y>0.$ So, $Ysim Exp(2)$ or $Ysim chi^2_2.$



But if $F$ is not continuous, i.e, there is jump in $F$, then $F(X)$ might not be uniformly distributed.






share|cite|improve this answer












It's easy if $F$ is continuous. In that case $P(F(X)leq t)=P(Xleq F^{-1}(t))=F(F^{-1}(t))=t$ for $0<t<1.$ So, $F(X)sim U(0,1).$ $P(-2log F(X)leq y/2)=P(log F(X)geq -y/2)=P(F(X)geq e^{-y/2})=1-e^{-y/2}$ for $y>0.$ So, $Ysim Exp(2)$ or $Ysim chi^2_2.$



But if $F$ is not continuous, i.e, there is jump in $F$, then $F(X)$ might not be uniformly distributed.







share|cite|improve this answer












share|cite|improve this answer



share|cite|improve this answer










answered Jan 4 at 1:17









John_Wick

1,436111




1,436111












  • We can say $P{Y leq y}=1-F(G(e^{-y/2)}))$ whether or not $F$ is continuous, where $G(t)=inf {x:F(x) geq t}$. If $F$ is continuous then $Fcirc G$ is the identity function.
    – Kavi Rama Murthy
    Jan 4 at 5:56












  • @kotsossgouras The first $y/2$ is a misprint; it should say $y$.
    – J.G.
    Jan 4 at 7:55










  • how we can show that F^-1(F(X))=X ??
    – kotsos sgouras
    Jan 4 at 12:34


















  • We can say $P{Y leq y}=1-F(G(e^{-y/2)}))$ whether or not $F$ is continuous, where $G(t)=inf {x:F(x) geq t}$. If $F$ is continuous then $Fcirc G$ is the identity function.
    – Kavi Rama Murthy
    Jan 4 at 5:56












  • @kotsossgouras The first $y/2$ is a misprint; it should say $y$.
    – J.G.
    Jan 4 at 7:55










  • how we can show that F^-1(F(X))=X ??
    – kotsos sgouras
    Jan 4 at 12:34
















We can say $P{Y leq y}=1-F(G(e^{-y/2)}))$ whether or not $F$ is continuous, where $G(t)=inf {x:F(x) geq t}$. If $F$ is continuous then $Fcirc G$ is the identity function.
– Kavi Rama Murthy
Jan 4 at 5:56






We can say $P{Y leq y}=1-F(G(e^{-y/2)}))$ whether or not $F$ is continuous, where $G(t)=inf {x:F(x) geq t}$. If $F$ is continuous then $Fcirc G$ is the identity function.
– Kavi Rama Murthy
Jan 4 at 5:56














@kotsossgouras The first $y/2$ is a misprint; it should say $y$.
– J.G.
Jan 4 at 7:55




@kotsossgouras The first $y/2$ is a misprint; it should say $y$.
– J.G.
Jan 4 at 7:55












how we can show that F^-1(F(X))=X ??
– kotsos sgouras
Jan 4 at 12:34




how we can show that F^-1(F(X))=X ??
– kotsos sgouras
Jan 4 at 12:34



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