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In probability and statistics, a probability distribution assigns a probability to each measurable subset of the possible outcomes of a random experiment, survey, or procedure of statistical inference.

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A variation of the law of large numbers for random points in a square

Given $n^2$ i.i.d. uniform points in $[0,1]^2$, the goal is to draw a configuration of $cn$ vertical lines and $cn$ horizontal lines such that in each small rectangle there is at most one marked point …
Yuval Peres's user avatar
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19 votes

What makes Gaussian distributions special?

If the random vector $(X,Y)$ in the plane has independent coordinates and a rotation-invariant distribution, then it is Gaussian.
8 votes
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Distribution of the first occurrence of a maximum (record) run of zeros in the digits of a n...

The length $R_N$ of the longest run in the first $N$ digits satisfies $R_N/\log_b(N) \to 1$ almost surely as $N \to \infty$, as first proved by Renyi, see the discussion in [1]. (Many references focus …
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6 votes
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Is there a 1/poly(n) or 1/polylogn upper-bound for this tail bound?

Let $A:=\Bigg\{\bigg\vert\dfrac{\sum_{j=1}^n(\sum_{i=1}^n a_{ij})^2}{n^2} -1\bigg\vert > \epsilon\Bigg\}\,$ denote the event in question. We will show that $\operatorname{P}(A)\le C_{\epsilon}/n$ f …
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6 votes
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Sum of random variables are equal in distribution

There is$^*$ a counterexample in the atomic case, see below, so we will assume that $(\Omega, \mathrm{P})$ is a non-atomic standard Lebesgue probability space (so it is Isomorphic to the unit interval …
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3 votes
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How to derive this change of measure identity in multi-armed bandits?

Shishir, this is quite elementary: write the probability $P_2(\omega)$ of any individual bit sequence $\omega$ as $P_1(\omega) f(\omega)$ where by definition, $f(\omega)=\exp(-\hat{kl}_n)$. Finally, s …
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3 votes

Samples from a modified Bernoulli

Perhaps most relevant is [1] which discusses this construction and reduces the general case to $c=2$. See Theorem 1 and proposition 15 there. Note that $cp \le 1$ is not a sufficient condition; an in …
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3 votes
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Distribution of a stopped random sum, with subexponential stopping time

The hypothesis implies that $M_k=[e^{\sum_{n=1}^k X_n}]$ is a supermartingale, with $M_0=1$. Then the optional stopping theorem for positive supermartingales implies the requested inequality. (see e. …
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2 votes
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On the speed of divergence of the converse of the Strong law of large numbers

Such a sequence $a_n$ does not exist even for a well studied example like returns to the origin of simple random walk in one dimension. If $X_i$ denotes the number of steps from the $i-1$ time the wal …
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2 votes

Bounded difference functions and sub-Gaussian random variables

The implication goes the other way. The "standard" inequality you quote, usually called McDiarmid's inequality is derived from the second inequality that you ask about. See e.g. http://empslocal.ex.a …
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2 votes
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Minimum mean over all random variables subject to logarithm constraint

Assume $X>0$ a.s. (so the constraint can be satisfied) and write $Y=\log X$. By Jensen's inequality (https://en.wikipedia.org/wiki/Jensen%27s_inequality), $\mathbb{E} X \ge e^{\mathbb{E} Y}=e^C$, so …
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2 votes
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Stationary and limiting distributions

For Markov chains, a very useful condition is Harris recurrence, see https://en.wikipedia.org/wiki/Harris_chain. This has been generalized to continuous time, see https://www.jstor.org/stable/3690386? …
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1 vote

CLT for Martingales

This Theorem is a direct consequence of the Skorohod representation of Martingales. You can find it, along with many variants, in Hall, Peter, and Christopher C. Heyde. Martingale limit theory and its …
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1 vote

Find $\inf_{P_{X_1,X_2}}P_{X_1,X_2}(\|X_1-X_2\| > 2\alpha)$ , where $\alpha > 0$ and inf is ...

As Iosif wrote, the conjecture does not hold. Suppose $\alpha=1$ and $X_1$ takes the values 0,1,2 with equal probability and $X_2$ takes the values 0,2 with equal probability. Then $h(1)=0$ but transl …
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1 vote
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Exponential upper bounds for sums of martingale differences

Let $J$ take the value $M$ with probability $1/M^2$ and the value 1 with probability $1-1/M^2$. Let $R_i$ be i.i.d. $\pm 1$ valued random variables of of mean zero, and define $X_i:=JR_i$. Then for $ …
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