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Applied and theoretical statistics: e.g. statistical inference, regression, time series, multivariate analysis, data analysis, Markov chain Monte Carlo, design of experiments.

7 votes

Generate Bernoulli vector with given covariance matrix

I'm going to provide two algorithms here: A super-exponential-time solution that works in all cases. A polynomial-time solution that applies if the mean values are known and if a certain matrix is p …
Bill Bradley's user avatar
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2 votes
Accepted

Constructing a Bernoulli random variable for ratio of Bernoulli weights

The obstruction that Bjørn Kjos-Hanssen describes can be made even worse-- it applies to any algorithm (not just von Neumann's trick) and also applies to randomized algorithms (i.e. even if the number …
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1 vote

How to sample uniformly from singular matrices

This is an MCMC algorithm for uniform sampling over singular $n$ by $n$ Bernoulli matrices. Let $H$ (for "hypercube") be the set of all 0/1 vectors of length $n$. One step of the MCMC algorithm is a …
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0 votes

Removing outliers from circular average data

First, in case you haven't run across this before, a classic reference for this area of statistics is Mardia and Jupp's Directional Statistics, which includes a number of measures capturing circular a …
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3 votes

How to sample uniformly from singular matrices

[Edit: After improving the rejection sampling algorithm and running it on a more powerful computer, I was able to extend my earlier numerical experiments. Improvements are described below in square b …
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2 votes
Accepted

Multinomial transformation for matrices

At the suggestion of the original poster, I am summarizing an alternate answer that has a few strengths relative to my original answer. It is related to the question and answer at this MathOverflow Q …
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2 votes
Accepted

Closure of random rotations

Yoav Kallus' comment above is correct; I'm going to sketch a few of the details below for the sake of completeness. Yoav points out that if we choose $X$ with parameter $$F=\begin{bmatrix}a&0&0\\0&0& …
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2 votes

Multinomial transformation for matrices

(Edited to fix a bug.) I think the following bijection will do what you want. For $1\leq i,j\leq n-1$, define $$r_{ij}=\log(p_{ij}/p_i)$$ Given the $r_{ij}$ and the marginals, we can recover the $p …
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1 vote
Accepted

How to perform Importance Sampling with Prior Information

Having explicit bounds on $\mathbb{E}[f(X)]$ does not appear to be useful. The variance can still be arbitrarily large, and the variance governs the rate of convergence for MC sampling. And if the v …
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2 votes
Accepted

Tightness of probabilty distributions

I think this conjecture is false, that is, there does not necessarily exist a subsequence that converges to a true probability distribution. Consider the following situation: Let $Q=(1,0,0,0,...)$, …
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1 vote

log-like distance between probability distributions

What about the symmetric-ized KL divergence? $$D(p,q) + D(q,p)$$ Recalling that $$D(p,q) = \sum_x p(x) \log \left(\frac{p(x)}{q(x)}\right)$$ then the $\log(p/q)$ is the order of magnitude of the ratio …
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2 votes

What's the cumulative probability of these particular bags of liquorice allsorts?

I think the OP is re-inventing Fisher's Exact Test, so perhaps an examination of that may be clarifying. FWIW, questions like this might be better suited to CrossValidated, which is a StackOverflow si …
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1 vote

Strategy optimization based on biased data

I don't understand the specifics of the gateway problem well enough to comment, but on the broader question of "how do I perform inference or optimization when I have observational data, and it's prob …
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7 votes
1 answer
291 views

Closure of random rotations

Are matrix Fisher random variables closed under multiplication? For those unfamiliar with the jargon, let me unpack the terms above and repose my question. This is a question about probability distrib …
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6 votes
1 answer
244 views

Violating an order statistic inequality?

[Edit: for posterity, I'm adding two small comments to the code explaining how to fix it, in light of Iosef Pinelis' answer below. Look for "Should be:" to find the corrections.] Suppose we draw a sam …
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