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1
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0answers
170 views

Why this two model have same probability distribution?

(1) Consider the following method of generating a random tree with $n$ nodes. First expand the root node into two branches. Then expand one of the two terminal nodes at random. At time $k$, ...
1
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2answers
522 views

Distribution of Maximum of a uniform multinomial distribution

Hello, I'm working with a data structure which uses a uniform distribution to bucket the inputs into $k$ buckets. The efficiency of the structure is bounded by the $\frac{k_{max}}n$, where $n$ is the ...
1
vote
1answer
276 views

Azuma's Inequality when the conditions hold with high probability?

In Azuma's Inequality, is the statement true when $|X_k - X_{k-1}| < c_k$ almost surely rather than with probability 1? If not, is there another result which gives strong concentration when the ...
3
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0answers
649 views

E[ | X - Y | ] where X and Y are independent Poisson random variable

What is the expected value of the absolute difference of two independent Poisson variables? E[ |X - Y| ] Seems like an easy question but I haven't found an easy solution. I've split the double sum ...
1
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1answer
152 views

Tail of solutions of a stochastic differential equation

As we know, solution to $dX_t=\mu dt+\sigma dW_t$ is normal distributed and is light tailed; solution to $dX_t=\mu X_tdt+\sigma X_t dW_t$ is log-normal distributed and is heavy tailed. Is there any ...
1
vote
1answer
292 views

Product of densities of a wrapped normal distribution

The density of a wrapped normal distribution is given by $$\frac{1}{\sigma \sqrt{2\pi} }\sum _{k=-\infty }^{\infty }\text{Exp}\left[\frac{-(\theta -\mu -2\pi k)^2}{2\sigma^2}\right]$$ Considering two ...
1
vote
2answers
357 views

measuring distance between probability measures only at the tail

Is there any official (i.e., to be found in probability books) metric for the distance between two probability measures, defined only on a subset of their support? Take, for example, the total ...
1
vote
1answer
125 views

The degrees in a random subgraph

Fix some positive integers $N$ and $d_k$, $k=1,2,\dots$ with $N=\sum_{k=1}^\infty d_k$. Suppose you have a graph $G$ taken randomly uniformly among the set of all (unoriented) graphs with $N$ ...
2
votes
2answers
4k views

Distance metric between two sample distributions (histograms)

Context: I want to compare the sample probability distributions (PDFs) of two datasets (generated from a dynamical system). These datasets depend on a set of parameters, and I want a concise way to ...
4
votes
2answers
1k views

Convergence of moments implies convergence to normal distribution

I have a sequence $\{X_n\}$ of random variables supported on the real line, as well as a normally distributed random variable $X$ (whose mean and variance are known but irrelevant). I know that the ...
0
votes
1answer
161 views

Derivative of the CDF of a family of random variables

Suppose I have a r.v. $Z = X + \alpha Y$ and that $F_Z$ is the probability distribution function of $Z$. If we think of the probability $p = F_Z(q) = \mathbb{P}(X+\alpha Y < q)$ as a function $p = ...
2
votes
3answers
3k views

Integration of the product of pdf & cdf of normal distribution [closed]

Denote the pdf of normal distribution as $\phi(x)$ and cdf as $\Phi(x)$. Does anyone know how to calculate $\int \phi(x) \Phi(\frac{x -b}{a}) dx$? Notice that when $a = 1$ and $b = 0$ the answer is ...
3
votes
2answers
283 views

Continuity of hitting distributions

Hi everybody Let $U$ be the domain (as shown in the picture) and $\bar{U}$ its closure, further more set $\partial_r U$ to be the reflecting boundary and $\partial_a U$ the absorbing one. The process ...
0
votes
1answer
238 views

Is it known that every PDF continuous in all $R^n$ has a maximum? [closed]

I'm working with maximum a posteriori estimation and managed to show that every probability density function that is continuous in all $R^n$ always has at least one global maximum. I've search around ...
0
votes
1answer
405 views

Marginalizing over discrete and continuous random variables

Suppose we have a joint distribution $P(D,X,L) = P(D|X)P(X|L)P(L)$. Here, D and L are discrete but X is a continuous random variable. I want to compute $P(D=d)$. How do I do this numerically? The fact ...
0
votes
2answers
758 views

Multivariate Power Law distributions?

Is there a text books or publications that describes multivariate power law/pareto distributions?
1
vote
0answers
384 views

Can you prove the monotonicity of the function (or find a counter example)?

Let $X$ be a non-negative random variable that is drawn from a cumulative distribution function $F(\cdot)$, pdf $f(\cdot)$ and mean $E[x]$. $k$, $c$, $v_l$ and $v_h$ $(v_h>v_l)$ are non-negative ...
2
votes
1answer
615 views

on the difference of exponential random variables

Assume two random variables X,Y are exponentially distributed with rates p and q respectively, and we know that the r.v. X-Y is distributed like X'-Y' where X',Y'are exponential random variables, ...
6
votes
2answers
280 views

If Mean Residual Lifetime is approximately constant, Residual Lifetime is Approximately Exponential in a Strong Sense

Suppose the "mean residual lifetime," $\mathbb{E}[X-x|X≥x]$ is approximately constant for large $x$. Then, I believe that the conditional tail distribution is approximately exponential, in the sense ...
0
votes
0answers
140 views

Projection of a probability distribution according to another one,

Hi, (Please forgive me if my question is vague or trivial) Let a normal distribution $P(\mu, \sigma)$ and a poisson distribution $Q(\lambda)$. I want to find a distribution $Q'$ that is : a ...
1
vote
2answers
238 views

Limit of a rescaled random sum of i.i.d. random variables

Consider a sequence of i.i.d. random variables $(X_i)_{i \in \mathbb N}$ and let $S_n=X_1+\dots+X_n$ For every $\alpha \in ]0,+\infty[$, let $N(\alpha)$ be a discrete random variable on $\mathbb N$, ...
0
votes
1answer
128 views

a function of Bernoulli variables?

Let $X_1,X_2,...,X_n$ be a fixed number of Bernoulli random variables. My problem is to find a distribution for $Y$ such that for some function $f$, we have $Y=f(X_1,X_2,...,X_n)$. There are two ...
-1
votes
1answer
305 views

Composed function made Lebesgue integrable?

Let $p(x)$ be a probability density function on the unbounded set $X \subseteq \mathbb{R}^n$, so that $\int_X p(x) dx = 1$. Let $F: X \rightarrow \mathbb{R}_{\geq 0}$ a measurable but non-integrable ...
5
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0answers
140 views

what books to read to quickly understand adiabatic approximation

Hi group, I'm a theoretical ecologist with fairly adequate training in applied math (ODE, linear algebra, applied probability, some PDEs). In my current work, I've encountered the use of adiabatic ...
3
votes
0answers
180 views

References for this game

Hello everybody, I would like to know how the following game is known in the literature and, possibly, to have references for related papers. Description of the game: Fix a space $X$ and two Borel ...
5
votes
3answers
183 views

What does it mean to sample a value x* from f(x)?

This might be a really elementary question, but I'm not sure what it means. I have a density function f(x). How do I sample a value from f? For known distributions there are functions in R which do it ...
0
votes
2answers
221 views

compound distribution in Bayesian sense vs. compound distribution as random sum?

I'm trying to sort out two different uses of the term "compound distribution" and figure out the relationship. The Wikipedia article on compound distribution -- which I wrote -- defines a compound ...
0
votes
2answers
301 views

Do these random variables follow Gaussian distribution?

Say that a random variable $X$ follows the Gaussian distribution $\mathcal{N}(\mu, \sigma)$. Then will the ceiling $\lceil X\rceil$, the floor $\lfloor X\rfloor$, and the rounding $\lfloor X\rceil$ ...
9
votes
1answer
551 views

Montgomery's pair correlation function without RH?

In the theory of the Riemann zeta function, Montgomery's Pair correlation function is defined as $$ F(\alpha) = \frac{1}{N(T)} \sum_{T < \gamma, \gamma' < 2T} T^{i \alpha (\gamma - \gamma')} ...
1
vote
2answers
874 views

Variance of exponential random variable

For a random variable $\xi$, what bounds can be achieved for Var $e^{\xi}$ in terms of E$\xi$ and Var $\xi$?
0
votes
1answer
147 views

Copulas and marginals thereof

Hello everyone, I recently became aware of the existence of the copula concept. So, I have been reading a few things about copulas lately, but I cannot seem to find information on the following ...
7
votes
2answers
309 views

Entropy conjecture for distributions over $\mathbb{Z}_n$

Suppose we have two independent random variables $X$ (with distribution $p_X$) and $Y$ (with distribution $p_Y$) which take values in the cyclic group $\mathbb{Z}_n$. Let $Z = X +Y$, where the ...
4
votes
2answers
2k views

Sum of Squares of Normal distributions

Given $X_i \sim \mathcal{N}(\mu_i,\sigma_i^2)$, for $i = 1,\dots,n$. How does one find the distribution of $D = \sum_{i=1}^n X_i^2$? In the case that all the standard deviations are the same (i.e. ...
2
votes
2answers
262 views

Scale random variables in a way they have equal probabilities of being minimal

I have several positive random variables $x_i,\ i=1,...,N$ taken from different unknown distributions (these distributions can be closely approximated by log-normal if needed). I can sample these ...
4
votes
0answers
169 views

probabilistic terminology for polynomials with positive coefficients

Given a polynomial $P(x) = p_0 + p_1 x + p_2 x^2 + ... + p_n x^n$ with non-negative coefficients, is there a standard name for (the function of $p_1,...,p_n$ equal to) the variance of an ...
2
votes
0answers
184 views

Proving that an increasing iterative sequence increases at a decreasing rate

In this question Proving a sequence of integrals increases (iterated minimax distributions) Pietro Majer proved that $$\int_0^1F_n(x) dx \leq \int_0^1F_{n+1}(x) dx$$ when $$F_n(x) = ...
10
votes
2answers
413 views

A Conjecture on the Density of a subset of integers

Let $X$ denote the largest subset of odd integers with the property that every exponent in the prime factorization of any $x \in X$ belongs to $X$. The conjecture states that the density of $X$ among ...
2
votes
1answer
198 views

Applications of this project

Hi Guys, Just wondering if you could suggest applications of distribution of the supremum of a fractional Brownian motion process with a drift ? Also if you could possibly recommend how to approach ...
0
votes
0answers
107 views

Joint Probability that contains a variable and its Fourier Transform

Given the vector $\mathbf{d}$, where $\mathbf{d}\in\mathbb{C}^{N\times 1}$, we have two variables $X = \mid\mathrm{F}[d]\mid^2,\quad\quad X\ge 0$ $Y = a+b (\mathrm{d}^H\mathrm{d})\quad Y\ge 0$ ...
8
votes
3answers
477 views

A Variance-Tail Description for Continuous Probability Distributions

Start with a continuous probability distribution given by a density function f(x). Let X be a real random variable whose distribution is given by the probability distribution. I would like to ask ...
12
votes
1answer
597 views

2/3 power law in the plane

I've recently come across a particular problem whose solution turns out to be a probability distribution given by $f(x) = \alpha \|x\|^{-2/3}$ in the unit disk in $\mathbb{R}^2$ and zero elsewhere (I ...
3
votes
0answers
274 views

Is this probability distribution known in the literature?

In some work I was doing I derived a probability distribution that I do not recognize. Is it a known distribution? $\Pr(X\le ...
0
votes
1answer
302 views

Expectation of little o in probablity [closed]

If I have $Z=o_p(1)$ where $o_p$ is the little-o in probability. I'm interested in find some properties about $E(Z)$. My first idea was $E(Z)=E(Z (1_{Z>\varepsilon} + 1_{Z\leq\varepsilon}) ) ...
3
votes
1answer
337 views

Cover a line segment randomly with smaller line segments

Covering a circle randomly with arcs has been well studied in the past (Geometric Probability - Solomon). But the problem when the circle is changed to a line segment doesn't seem to have been ...
5
votes
1answer
721 views

Eigenvalue distributions of finite dimensional Wishart matrices

I am trying to obtain the eigenvalue distribution of a finite dimensional Wishart matrix. Let $A_{n\times n}\sim\mathbb{W}(\Sigma_{n\times n},m)$ where $\mathbb{W}(\Sigma_{n\times n},m)$ denotes the ...
14
votes
0answers
362 views

Erdos-Kac for squarefree numbers

In its usual form, the Erdos-Kac Theorem states that if $f(n) : \mathbb{N} \rightarrow \mathbb{R}$ is a strongly additive function with $|f(p)| \le 1$ for all primes $p$, then $$\frac{\\#\{n \le x : ...
5
votes
1answer
197 views

Is the maximum tree-path length distributed lognormally (in the limit) ?

Consider a full binary tree with $k>10$ levels. Let the lengths of individual edges in this tree be i.i.d. random variables with finite moments. Then total lengths of the $2^{k-1}$ source-to-sink ...
0
votes
1answer
384 views

Find the joint distribution

Say $\boldsymbol{\beta}$ is a random n-vector having the multivariate normal distribution with mean $\boldsymbol{b}$ and covariance matrix $\boldsymbol{S}$. And let $\boldsymbol{x}_1$ and ...
0
votes
1answer
425 views

maximum likelihood of gamma distribution computer calculation

My problem is that given a dataset, I want to program fitting a gamma distribution on this data by estimating the two parameters(shape and the scale parameters) using Maximum Likelihood Estimation. I ...
2
votes
2answers
466 views

probability computation involving sum of log-normal random variables

How do I compute the following? $$ \mathrm{Prob}\left( \sum_{i=1}^N x_i >1\right) = ?$$ where $x_i \sim \mathrm{Log}\mathcal{-N}(\mu_i, \sigma_i^2)$. AFAIK, we do not know how the sum of ...