## wrong statistics

Posted in Books, Statistics with tags , , , , , , , , , on November 2, 2022 by xi'an

The Guardian reported today on a larger probability for men drivers to kill/injure a pedestrian, when compared with female drivers. Which is somewhat misleading. The figures report on the probability that the driver is male, given a serious collision occurred. But it does not directly reflect on the (very probable!) gender difference in dangerousity, i.e. the difference in the probabilities that a female driver vs. a male driver run over a pedestrian because it does not account for the probable difference in women vs. men drivers on the road at any given time, or on the mileage accumulated by each gender over a given year. Which differs by almost two…  (As mentioned in the article, a disproportionate percentage of accidents are due to vans, which again are more likely to be driven by men.)

## pool etiquette [and lane rage]

Posted in Statistics with tags , , , , , , , , , on March 15, 2019 by xi'an

A funny entry in The Guardian of today about what turns swimmers mad at the pool. A form (foam?) of road-rage in the water… Since I have started a daily swim since mid-December to compensate for my not-running for an indeterminate length of time, I can primarily if irrationally relate to the reactions reported in the article. About the pain of passing other swimmers and being brushed or kicked by faster runners oops swimmers trying to squeeze in the middle (of nowhere). Irrationally so because at  a rational level there is nowhere to go really, except the end of the lane and back, which means waiting or turning back earlier not much of an imposition. But still feeling a sort of “road rage” when I cannot turn back and start again without delay… I have been thinking for the past weeks (while going back and forth, back and forth, dozens of times) of ways to rationalize the whole operation but cannot see a way to make all swimmers go exactly the same speed in a given lane, if only because most swimmers switch stroke between lengths. Except me as I can only and barely handle the breast stroke, thanks to lessons from Nick!, stroke than many seem to resent. To the point of calling for breast-stroke free lanes… Rationally, I think the problem is the same with every activity involving moving at different relative speeds on a busy lane. Runners get annoyed at breaking their pace, cyclists at braking or worse!, touching ground. It is just more concentrated in a 25m swimming lane on a busy day. (Which is why I really try to optimise my visits to the pool to be in the early morning or in the mid-afternoon. And again and again promise myself to skip the dreadful Sunday morning session!) L’enfer, c’est les autres, especially when they swim at a different pace!

## drivers are not interested in maths formulas

Posted in Kids, pictures, Statistics, Travel, Wines with tags , , , , , , , on January 1, 2018 by xi'an

An appalling discussion on the French public radio (France Inter) this morning about reducing the average speed on bidirectional roads from 90 km/h to 80 km/h, when the representative of “40 millions d’automobilistes”, a driver lobby with a few hundred thousands members, called the chain to protest against this potential move by the Macron government. With arguments ranging from being unjust for the rural parts of the country [the reduction in speed adds seven minutes per hour!], to predicting the regulation to be ignored by most drivers, to a lack of democracy [as if driving a car was a fundamental right! What’s next?! The right to bear arms?!], and finally to denying arguments based on econometric models [dismissed as “maths formulas”], like Nilsson’s.