## hands-on probability 101

Posted in Books, Kids, pictures, Statistics, University life with tags , , , , , , , , , on April 3, 2021 by xi'an

When solving a rather simple probability question on X validated, namely the joint uniformity of the pair

$(X,Y)=(A-B+\mathbb I_{A

when A,B,C are iid U(0,1), I chose a rather pedestrian way and derived the joint distribution of (A-B,C-B), which turns to be made of 8 components over the (-1,1)² domain. And to conclude at the uniformity of the above, I added a hand-made picture to explain why the coverage by (X,Y) of any (red) square within (0,1)² was uniform by virtue of the symmetry between the coverage by (A-B,C-B) of four copies of the (red) square, using color tabs that were sitting on my desk..! It did not seem to convince the originator of the question, who kept answering with more questions—or worse an ever-changing question, reproduced in real time on math.stackexchange!, revealing there that said originator was tutoring an undergrad student!—but this was a light moment in a dreary final day before a new lockdown.

## ten recommendations from the RSS

Posted in Statistics, University life with tags , , , , , , , , , , , on March 21, 2021 by xi'an

‘Statistics have been crucial both to our understanding of the pandemic and to our efforts to fight it. While we hope we won’t see another pandemic on this scale, we need to see a culture change now – with more transparency around data and evidence, stronger mechanisms to challenge the misuse of statistics, and leaders with statistical skills.’

• Invest in public health data – which should be regarded as critical national infrastructure and a full review of health data should be conducted
• Publish evidence – all evidence considered by governments and their advisers must be published in a timely and accessible manner
• Be clear and open about data – government should invest in a central portal, from which the different sources of official data, analysis protocols and up-to-date results can be found
• Challenge the misuse of statistics – the Office for Statistics Regulation should have its funding augmented so it can better hold the government to account
• The media needs to step up its responsibilities – government should support media institutions that invest in specialist scientific and medical reporting
• Build decision makers’ statistical skills – politicians and senior officials should seek out statistical training
• Build an effective infectious disease surveillance system to monitor the spread of disease – the government should ensure that a real-time surveillance system is ready for future pandemics
• Increase scrutiny and openness for new diagnostic tests – similar steps to those adopted for vaccine and pharmaceutical evaluation should be followed for diagnostic tests
• Health data is incomplete without social care data – improving social care data should be a central part of any review of UK health data
• Evaluation should be put at the heart of policy – efficient evaluations or experiments should be incorporated into any intervention from the start.

## a journal of the plague year [are we there yet?!]

Posted in Books, Kids, Mountains, pictures, Travel with tags , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , on March 20, 2021 by xi'an

Read the next volume of the Witcher series, Baptism of Fire, with even less enthusiasm than for the previous one, as the momentum of the series seems to have stalled… (Despite reading some highly positive reviews.) Some dialogues are funny enough, along with progressive views not particularly common in fantasy, like the support of reproductive rights, incl. abortion (and even less supported in the home country of the author, Andrzej Sapkowski!). But overall, not much happening and too much infodump!

Baked Ethiopian lentils & spinach mix, to get along with a slow cooking Ethiopian beef stew. And cooked more Venetian dishes. And had a great Korean streetfood dinner at (or from) MamiBaba by Quinsou, near Montparnasse, with pajeon (the cousin to okonomiyaki!) and kimchee. Accompanied by a first attempt at baking a chocolate pie.

Watched a few episodes of Alice in Borderland, vaguely suggested as hearsay by my daughter, but despite the fascinating scenes of an empty Tokyo, the plot is not particularly engaging, the tricks towards solving the game often lame, and the characters are not developed at all. Then watched Kurosawa’s Creepy, a gripping if not particularly realist psychological thriller that was premiered at the 2016 Berlin Film Festival. And reminded me of the much more disturbing Losey’s The Servant

Read two further volumes of John Harvey’s Charlie Resnick, in a random order, volumes that I found in and returned to the exchange section in front of our library as usual. And which I found almost as good as the first one, with its insistence on the humanity of each of the characters rather than indulging in manicheism. References to jazz pieces got a wee bit annoying by the third volume… And there is a maximal number of rye bread sandwiches with Polish pastrami I can swallow!

Watched also for the first time the fascinating The Wild Goose Lake (南方车站的聚会 which translates as A Rendez-Vous at a Station in the South), by Diao Yinan, a 2019 Cannes Festival selection, a psychological and violent noir film taking place in Wuhan among local gangs, when a gang boss kills by mistake a policeman after a very gory episode. The classical story line of the chase à la A bout de souffle is both tenuous and gripping, with an painful attention to colour and lightings, most scenes taking place at night with ghastly lights, with an intentional confusion between gangs of criminals and groups of cops, the final scene in full daylight making everything else sounding like a bad dream. The two main characters are striking, with an outlandish swan-like actress Gwei Lun-Mei. This also led me to watch the earlier Black Coal Thin Ice, which I also found impressive in terms of filming [that makes the cold and snow in this Northern city almost perceptible!] and definition of characters, once again involving Gwei Lun-Mei as the central, almost mute, and doomed, woman, but puzzling in terms of psychology and scenarios. (The shootout in the gallery is plain ridiculous imho.)

## race against COVID [mural]

Posted in Books, Kids, pictures, Running, Travel with tags , , , , , , , on March 7, 2021 by xi'an

## a journal of the plague year [soon to turn one…]

Posted in Books, Kids, Mountains, pictures, Travel with tags , , , , , , , , , , , , , , , , , , , , , , , on March 6, 2021 by xi'an

Read in a few Sunday hours Living proof by John Harvey, a 1995 novel that I had found in the book exchange section of our library. A very easy read but rather enjoyable with several stories within stories and books within books. The resolution of the main murder mystery was disappointing but I enjoyed the inclusion of real artists like Ian Rankin and Mark Timlin. With a pastiche of P.D. James. And plenty of jazz references. Plus two characters meeting while studying at Warwick. And some shared glimpses of Nottingham like the statue of Robin Hood and the troglodyte Ye Olde Trip to Jerusalem. where I was once  invited for a pint… The story takes place during and around Nottingham’s Shots in the Dark festival. I hence grabbed another volume in the library in prevision of another lazy afternoon!

Baked rather decent chapattis for a take-home Bengali dinner but ruined the pan and started the fire alarm! Also tried to bake tortillas but mixed up the proportions of flour and water, ending up with a type of galette or injera instead (which worked as a container for the fajitas!).

Eventually watched the last two episodes of the Queen’s Gambit, but found them somewhat disappointing, between the main characters’ attitude that did not feel in tune with the 1960’s, the French femme fatale who cannot pronounce Jardins du Luxembourg, and the somewhat rosy tale of two orphans achieving financial freedom and professional success before their majority. Also watched the Korean Space Sweepers after an exhausting day, with a very shallow plot and a complete disregard for physics.

Read the duology of Six of Crows and Crooked Kingdom, by Leigh Bardugo, set in the same universe as the Grisha novels. Which I had read five years ago and somewhat forgotten than these novels were written as young adult books, with a resulting shallow plot, so full of sudden changes of fortune that any worry for the (caricaturesque) characters vanishes (till the one point when one should have) in a definitive suspension of suspense. (The Guardian reviewed Six of Crows in the Children’s book review section, which feels rather inappropriate given the degree of abuse the teens in the novels are submitted to, with two girls surviving sexual enslavement in the local brothels.) Just like the Grisha novels were set in a postcard version of Russia, these novels are taking place in a similarly thin (pannenkoek) version of Amsterdam (with waffles as the only culinary delicacy!). I do realise these series have a huge fan base, to the point of leading to an incoming Netflix series. But I found the more elaborate Ninth House much more enjoyable… (In tune with this series of reviews, the second book includes a plague episode with a modicum of realism, at least in its early stages.)