Large-n limit of the distribution of the normalized sum of Cauchy random variablesLimit of a rescaled random sum of i.i.d. random variablesNon-normality of limit of random variablesOn the sum of uniform independent random variablesSum of independent random variablesHow to obtain the probability distribution of a sum of dependent discrete random variables more efficientlyRate of convergence of a test statistic towards a Gaussian random variableCalculating the expectation of a sum of dependent random variablesVariance of sum of $m$ dependent random variablesSum of random variables are equal in distributionA lower bound on the expected sum of Bernoulli random variables given a constraint on its distribution

Large-n limit of the distribution of the normalized sum of Cauchy random variables


Limit of a rescaled random sum of i.i.d. random variablesNon-normality of limit of random variablesOn the sum of uniform independent random variablesSum of independent random variablesHow to obtain the probability distribution of a sum of dependent discrete random variables more efficientlyRate of convergence of a test statistic towards a Gaussian random variableCalculating the expectation of a sum of dependent random variablesVariance of sum of $m$ dependent random variablesSum of random variables are equal in distributionA lower bound on the expected sum of Bernoulli random variables given a constraint on its distribution













13












$begingroup$


What is the large-n limit of a distribution of the following sample statistic:$$xequivdisplaystylefracsum^nX_i,sqrt,sum^nX_i^2,,$$ when sampling the Cauchy(0,1) distribution? Monte Carlo simulation indicates that convergence to this limit is quite fast, and that the resulting (symmetric) PDF has very sharp cusps at -1 and +1, but of course does not yield an analytic expression for this PDF - would anyone be able to find it?

Here is how the positive half of the PDF looks like:



enter image description here










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Honza is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
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  • $begingroup$
    A somewhat random remark: the limiting distribution is also the distribution of $X_1 / langle Xrangle_1$ if $X_t$ is the Cauchy process and $langle Xrangle_t$ is the quadratic variation process, a $tfrac12$-stable subordinator. I bet someone has studied the joint law of $X_t$ and $langle Xrangle_t$, but unfortunately I do not have time now to search for the reference.
    $endgroup$
    – Mateusz Kwaśnicki
    Jun 16 at 20:17
















13












$begingroup$


What is the large-n limit of a distribution of the following sample statistic:$$xequivdisplaystylefracsum^nX_i,sqrt,sum^nX_i^2,,$$ when sampling the Cauchy(0,1) distribution? Monte Carlo simulation indicates that convergence to this limit is quite fast, and that the resulting (symmetric) PDF has very sharp cusps at -1 and +1, but of course does not yield an analytic expression for this PDF - would anyone be able to find it?

Here is how the positive half of the PDF looks like:



enter image description here










share|cite|improve this question









New contributor



Honza is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.






$endgroup$











  • $begingroup$
    A somewhat random remark: the limiting distribution is also the distribution of $X_1 / langle Xrangle_1$ if $X_t$ is the Cauchy process and $langle Xrangle_t$ is the quadratic variation process, a $tfrac12$-stable subordinator. I bet someone has studied the joint law of $X_t$ and $langle Xrangle_t$, but unfortunately I do not have time now to search for the reference.
    $endgroup$
    – Mateusz Kwaśnicki
    Jun 16 at 20:17














13












13








13


4



$begingroup$


What is the large-n limit of a distribution of the following sample statistic:$$xequivdisplaystylefracsum^nX_i,sqrt,sum^nX_i^2,,$$ when sampling the Cauchy(0,1) distribution? Monte Carlo simulation indicates that convergence to this limit is quite fast, and that the resulting (symmetric) PDF has very sharp cusps at -1 and +1, but of course does not yield an analytic expression for this PDF - would anyone be able to find it?

Here is how the positive half of the PDF looks like:



enter image description here










share|cite|improve this question









New contributor



Honza is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.






$endgroup$




What is the large-n limit of a distribution of the following sample statistic:$$xequivdisplaystylefracsum^nX_i,sqrt,sum^nX_i^2,,$$ when sampling the Cauchy(0,1) distribution? Monte Carlo simulation indicates that convergence to this limit is quite fast, and that the resulting (symmetric) PDF has very sharp cusps at -1 and +1, but of course does not yield an analytic expression for this PDF - would anyone be able to find it?

Here is how the positive half of the PDF looks like:



enter image description here







pr.probability probability-distributions limit-theorems






share|cite|improve this question









New contributor



Honza is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.










share|cite|improve this question









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Honza is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.








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edited Jun 16 at 15:43









Carlo Beenakker

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asked Jun 16 at 14:37









HonzaHonza

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Check out our Code of Conduct.













  • $begingroup$
    A somewhat random remark: the limiting distribution is also the distribution of $X_1 / langle Xrangle_1$ if $X_t$ is the Cauchy process and $langle Xrangle_t$ is the quadratic variation process, a $tfrac12$-stable subordinator. I bet someone has studied the joint law of $X_t$ and $langle Xrangle_t$, but unfortunately I do not have time now to search for the reference.
    $endgroup$
    – Mateusz Kwaśnicki
    Jun 16 at 20:17

















  • $begingroup$
    A somewhat random remark: the limiting distribution is also the distribution of $X_1 / langle Xrangle_1$ if $X_t$ is the Cauchy process and $langle Xrangle_t$ is the quadratic variation process, a $tfrac12$-stable subordinator. I bet someone has studied the joint law of $X_t$ and $langle Xrangle_t$, but unfortunately I do not have time now to search for the reference.
    $endgroup$
    – Mateusz Kwaśnicki
    Jun 16 at 20:17
















$begingroup$
A somewhat random remark: the limiting distribution is also the distribution of $X_1 / langle Xrangle_1$ if $X_t$ is the Cauchy process and $langle Xrangle_t$ is the quadratic variation process, a $tfrac12$-stable subordinator. I bet someone has studied the joint law of $X_t$ and $langle Xrangle_t$, but unfortunately I do not have time now to search for the reference.
$endgroup$
– Mateusz Kwaśnicki
Jun 16 at 20:17





$begingroup$
A somewhat random remark: the limiting distribution is also the distribution of $X_1 / langle Xrangle_1$ if $X_t$ is the Cauchy process and $langle Xrangle_t$ is the quadratic variation process, a $tfrac12$-stable subordinator. I bet someone has studied the joint law of $X_t$ and $langle Xrangle_t$, but unfortunately I do not have time now to search for the reference.
$endgroup$
– Mateusz Kwaśnicki
Jun 16 at 20:17











1 Answer
1






active

oldest

votes


















15












$begingroup$

This desired large-$n$ limit of the distribution $P_n(x)$ is calculated in Limit Distributions of Self-normalized Sums (1973). The Cauchy distribution is the case $alpha=1$ on page 798. The singularity in $lim_nrightarrowinftyP_n(x)$ at $x=pm 1$ is logarithmic
$$P_n(x)rightarrow-pi^-2log|1-x^2|,$$
see equation (5.12) and figure 4 (reproduced below), while for large $|x|$ the decay is Gaussian.








share|cite|improve this answer









$endgroup$












  • $begingroup$
    Thanks for your help; the article you mention is as exhaustive as it could be - one has to accept that the asymptotic PDF is not a "pretty" function!
    $endgroup$
    – Honza
    Jun 16 at 22:29













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1 Answer
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active

oldest

votes








1 Answer
1






active

oldest

votes









active

oldest

votes






active

oldest

votes









15












$begingroup$

This desired large-$n$ limit of the distribution $P_n(x)$ is calculated in Limit Distributions of Self-normalized Sums (1973). The Cauchy distribution is the case $alpha=1$ on page 798. The singularity in $lim_nrightarrowinftyP_n(x)$ at $x=pm 1$ is logarithmic
$$P_n(x)rightarrow-pi^-2log|1-x^2|,$$
see equation (5.12) and figure 4 (reproduced below), while for large $|x|$ the decay is Gaussian.








share|cite|improve this answer









$endgroup$












  • $begingroup$
    Thanks for your help; the article you mention is as exhaustive as it could be - one has to accept that the asymptotic PDF is not a "pretty" function!
    $endgroup$
    – Honza
    Jun 16 at 22:29















15












$begingroup$

This desired large-$n$ limit of the distribution $P_n(x)$ is calculated in Limit Distributions of Self-normalized Sums (1973). The Cauchy distribution is the case $alpha=1$ on page 798. The singularity in $lim_nrightarrowinftyP_n(x)$ at $x=pm 1$ is logarithmic
$$P_n(x)rightarrow-pi^-2log|1-x^2|,$$
see equation (5.12) and figure 4 (reproduced below), while for large $|x|$ the decay is Gaussian.








share|cite|improve this answer









$endgroup$












  • $begingroup$
    Thanks for your help; the article you mention is as exhaustive as it could be - one has to accept that the asymptotic PDF is not a "pretty" function!
    $endgroup$
    – Honza
    Jun 16 at 22:29













15












15








15





$begingroup$

This desired large-$n$ limit of the distribution $P_n(x)$ is calculated in Limit Distributions of Self-normalized Sums (1973). The Cauchy distribution is the case $alpha=1$ on page 798. The singularity in $lim_nrightarrowinftyP_n(x)$ at $x=pm 1$ is logarithmic
$$P_n(x)rightarrow-pi^-2log|1-x^2|,$$
see equation (5.12) and figure 4 (reproduced below), while for large $|x|$ the decay is Gaussian.








share|cite|improve this answer









$endgroup$



This desired large-$n$ limit of the distribution $P_n(x)$ is calculated in Limit Distributions of Self-normalized Sums (1973). The Cauchy distribution is the case $alpha=1$ on page 798. The singularity in $lim_nrightarrowinftyP_n(x)$ at $x=pm 1$ is logarithmic
$$P_n(x)rightarrow-pi^-2log|1-x^2|,$$
see equation (5.12) and figure 4 (reproduced below), while for large $|x|$ the decay is Gaussian.









share|cite|improve this answer












share|cite|improve this answer



share|cite|improve this answer










answered Jun 16 at 15:37









Carlo BeenakkerCarlo Beenakker

84k9 gold badges199 silver badges303 bronze badges




84k9 gold badges199 silver badges303 bronze badges











  • $begingroup$
    Thanks for your help; the article you mention is as exhaustive as it could be - one has to accept that the asymptotic PDF is not a "pretty" function!
    $endgroup$
    – Honza
    Jun 16 at 22:29
















  • $begingroup$
    Thanks for your help; the article you mention is as exhaustive as it could be - one has to accept that the asymptotic PDF is not a "pretty" function!
    $endgroup$
    – Honza
    Jun 16 at 22:29















$begingroup$
Thanks for your help; the article you mention is as exhaustive as it could be - one has to accept that the asymptotic PDF is not a "pretty" function!
$endgroup$
– Honza
Jun 16 at 22:29




$begingroup$
Thanks for your help; the article you mention is as exhaustive as it could be - one has to accept that the asymptotic PDF is not a "pretty" function!
$endgroup$
– Honza
Jun 16 at 22:29










Honza is a new contributor. Be nice, and check out our Code of Conduct.









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