Author: xi'an

Computational Bayesian Statistics [book review]

This Cambridge University Press book by M. Antónia Amaral Turkman, Carlos Daniel Paulino, and Peter Müller is an enlarged translation of a set of lecture notes in Portuguese. (Warning: I have known Peter Müller from his PhD years in Purdue University and cannot pretend to perfect objectivity. For one thing, Peter once brought me frozen-solid […]

O’Bayes 2019: poster deadline extension

For potential participants to the ISBA O’Bayes 2019 conference in Warwick next June 28 – July 02, that is, almost everyone except the participants who have already submitted!, this post is to announce that the deadline for poster submission has just been extended till March 15, to account for BNP 12 potential participants having not […]

missing digit in a 114 digit number [a Riddler’s riddle]

A puzzling riddle from The Riddler (as Le Monde had a painful geometry riddle this week): this number with 114 digits 530,131,801,762,787,739,802,889,792,754,109,70?,139,358,547,710,066,257,652,050,346,294,484,433,323,974,747,960,297,803,292,989,236,183,040,000,000,000 is missing one digit and is a product of some of the integers between 2 and 99. By comparison, 76! and 77! have 112 and 114 digits, respectively. While 99! has 156 digits. […]

alternatives to EM

In an arXived preprint submitted to Computational Statistics & Data Analysis, Chan, Han, and Lim study alternatives to EM for latent class models. That is, mixtures of products of Multinomials. (First occurrence of an indicator function being called the “Iverson bracket function”!) The introduction is fairly extensive given this most studied model. The criticisms of […]

plenary speakers for BayesComp 20[20]

As a co-chair of the incoming ISBA BayesComp 2020 in Gainesville, Florida, 7-10 January 2020. I am very glad to broadcast that the four plenary speakers for the conference are David Blei (Columbia U) Paul Fearnhead (U Lancaster) Emily Fox (U Washington) Max Welling (U Amsterdam) There will soon be a call for contributed sessions, […]

estimation exam [best of]

Yesterday, I received a few copies of our CRC Press Handbook of Mixture Analysis, while grading my mathematical statistics exam 135 copies. Among the few goodies, I noticed the always popular magical equality E[1/T]=1/E[T] that must have been used in so many homeworks and exam handouts by now that it should become a folk theorem. […]

risk-adverse Bayes estimators

An interesting paper came out on arXiv in early December, written by Michael Brand from Monash. It is about risk-adverse Bayes estimators, which are defined as avoiding the use of loss functions (although why avoiding loss functions is not made very clear in the paper). Close to MAP estimates, they bypass the dependence of said […]

the adoration of the golden car

As the demonstrations by the “gilets jaunes” become a fixture of French Saturdays, the French government is gradually giving up on the reforms it had started and is in particular catering to the car [and motorbike] lobby that started the protests. The symbol itself comes from the yellow fluorescent jackets found in every car and […]

more concentration, everywhere

Although it may sound like an excessive notion of optimality, one can hope at obtaining an estimator δ of a unidimensional parameter θ that is always closer to θ that any other parameter. In distribution if not almost surely, meaning the cdf of (δ-θ) is steeper than for other estimators enjoying the same cdf at […]

Le Monde puzzle [#1081]

A “he said-she said” Le Monde mathematical puzzle (again in the spirit of the famous Singapore high-school birthdate problem): Abigail and Corentin are both given a positive integer, a and b, such that a+b is either 19 or 20. They are asked one after the other and repeatedly if they are sure of the other’s […]

revisiting the Gelman-Rubin diagnostic

Just before Xmas, Dootika Vats (Warwick) and Christina Knudson arXived a paper on a re-evaluation of the ultra-popular 1992 Gelman and Rubin MCMC convergence diagnostic. Which compares within-variance and between-variance on parallel chains started from hopefully dispersed initial values. Or equivalently an under-estimating and an over-estimating estimate of the MCMC average. In this paper, the […]

the future of conferences

The last issue of Nature for 2018 offers a stunning collection of science photographs, ten portraits of people who mattered (for the editorial board of Nature), and a collection of journalists’ entries on scientific conferences. The later point leading to interesting questioning on the future of conferences, some of which relate to earlier entries on […]

unbiased estimators that do not exist

When looking at questions on X validated, I came across this seemingly obvious request for an unbiased estimator of P(X=k), when X~B(n,p). Except that X is not observed but only Y~B(s,p) with s<n. Since P(X=k) is a polynomial in p, I was expecting s…