back from HKU

conditioning on zero probability events

An interesting question on X validated as to how come a statistic T(X) can be sufficient when its support depends on the parameter θ behind the distribution of X. The reasoning there being that the distribution of X given T(X)=t does depend on θ since it is not defined for some values of θ … Which is not correct in that the conditional distribution of X depends on the realisation of T, meaning that if this realisation is impossible, then the conditional is arbitrary and of no relevance. Which also led me to tangentially notice and bemoan that most (Stack) exchanges on conditioning on zero probability events are pretty unsatisfactory in that they insist on interpreting P(X=x) [equal to zero] in a literal sense when it is merely a notation in the continuous case. And undefined when X has a discrete support. (Conditional probability is always a sore point for my students!)

Acqua granda

[Email on my Ca’Foscari account today:]

Le sedi di Ca’ Foscari ubicate nel centro storico di Venezia rimarranno chiuse domani 14 novembre, per le verifiche di ripristino della funzionalità. Pertanto tutte le attività didattiche e amministrative e delle biblioteche nelle nostre sedi del centro storico saranno sospese.

postgraduate open day at Warwick [4 Dec]

The department of Statistics at the University of Warwick is holding an open day for prospective PhD students on 4 December 2019, starting at 2pm (with free lunch at 1pm). In the Mathematical Sciences Building common room (room MB1.02). The Director of Graduate Studies, Professor Mark Steel, and the PhD admissions tutors Professors Martyn Plummer and Barbel Finkelstadt Rand will give short presentations about what it means to do a PhD, what it means to do it at Warwick, the benefits of a PhD degree, and the application process.

Subsequently there will be an informal meeting, during which students have the possibility to ask questions and find out more about the different PhD opportunities at Warwick Statistics; in fact, we offer a very broad range of possibilities, giving a lot of choice for potential applicants. Current members of staff will be invited to participate, to discuss potential projects.

UK travel expenses will be covered by the Department of Statistics (standard class travel by public transport with pre-booked tickets). Please register if interested in this event.

Seoul sunrise [jatp]

more EU, another 50 years! [jatp]

garbage in the air

As I am flying today to Seoul, for the Fall meeting of the Korean Statistical Society, a somewhat interesting paper in the New York Times about switching to alternatives for airline catering (if not air travel), starting with the figure that a passenger generates on average 1.5kg of waste per flight. And pointing out the conflicting issues in recycling food waste in most countries as they see it as imported waste and potential imported pathogens.and biohazards… While getting rids of plastic items is a tiny step in the right direction, especially because airlines do not sort between different kinds of garbage, a major step would be to avoid replacing them by another disposable item, especially heavier ones. From getting rid of providing food and drink (except water) on short and medium-haul flights to aim at healthy foods that do not require packaging or utensils. Like fruits. And asking passengers to carry their own garbage when leaving the plane could also enhance the realisation of the amount of garbage they thus produced. (On a recent early morning flight between Paris and Birmingham, the plane supposedly could not leave until the late delivery truck had brought croissants and drinks, as if passengers could not have abstained for the 55mn the flight lasted, especially when most of them were sleeping…) Nowadays. I usually travel with a water bottle that I fill before boarding after security and often skip meals on flights, but it invariably proves difficult to ask flight attendants to use my own reusable cup rather than a single-use plastic cup.