sistema fallibile

Dal tgcom:

I due sei milionari di Napoli, centrati nella stessa ricevitoria con giocate piazzate a un giorno di distanza, sono il frutto di un errore. A spiegare quanto accaduto, il titolare della ricevitoria in Corso Vittorio Emanuele. In pratica i ricevitori avrebbero stampato due volte alcune delle combinazioni che la Sisal invia a ogni estrazione. “E’ stata una svista, abbiamo stampato due blocchi identici di schedine”, ha affermato il titolare.

La notizia della recente doppia vincita al superenalotto ha originato un fiume di commenti. Qualcuno parla di coincidenza, ma se debbiamo credere a Freud (e non solo a lui) le coincidenze non esistono. Che pensare allora?

Mettendo subito in chiaro che non ho alcun interesse a considerare le vari(opint)e ipotesi di un’estrazione truccata o pilotata, a mio avviso molto poco plausibili, vorrei presentare e discutere l’episodio come se fosse un semplice problema di calcolo delle probabilità,

demografia snumerata

Come in ogni materia, anche in demografia è comprensibile che qualche volta i numeri ingannino la persona inesperta. Per esempio, nella  recensione scritta per il lancio del (fantastico) motore Wolfram Alpha, la redattrice di LifeHacker Gina Trapani si meraviglia che sua nonna abbia un’aspettativa di vita migliore della sua, per poi imparare subito dopo dai commenti dei lettori che l’essere arrivata a una veneranda età non può che averla favorita: infatti, è cosa certa (e banale) che una settantenne, a prescindere dal numero di anni di vita che teoricamente le rimangono, vivrà almeno settan’anni, mentre non è altrettanto certo che lo stesso succeda a una qualunque una ragazza, anzi, è tanto meno certo quanto più la ragazza è giovane.

L’articolo Il paese delle culle piene, pubblicato su La Repubblica qualche giorno fa, è un altro esempio di ingenuità di cui vorrei commentare un passo in particolare.

colliderix

Il principio è semplice: occorre cliccare sui pezzi liberi, nella sequenza e nei tempi giusti, affinché le palle rosse e verdi, rotolando verso il basso per effetto della forza di gravità, riescano a toccare le forme dello stesso colore e puff! scomparire insieme a loro. Ma ogni livello è diverso dai precedenti e rappresenta una sfida inedita. Io ho trovato il 39esimo livello un piccolo capolavoro.

build your own pestering email reminder using Google docs

Let’s say you have a dentist appointment next Tuesday at 3 PM, so you configure the software to send you a reminder email at 2:30.

Then, if you’re anything like me, on the day of the appointment the reminder note arrives in your inbox and you dismiss it almost thoughtlessly, saying to yourself “Oh yeah. The dentist. I’ll get up and go in a second, as soon as I finish debugging this one function.”

The next time you blink your eyes, it’s eight o’clock in the evening. Not only have you missed your dentist appointment, but also your dinner.

When I’m in the zone, it’s hard to snap out of that reverie, so those online appointment reminder services don’t work very well for me.

But what if I could tell the software to send me a barrage of notifications? [...] That would probably get my attention, and I’d probably make it to my dentist appointment.

I know there are a zillion reminder services out there. But what if there was another one, capable of ridiculous, incessant pestering?

(from http://benjismith.net/index.php/2006/07/12/biz-idea-16-incessant-pestering/)


Important: Here I do not speak of simple reminders. I speak of pestering (or nagging, or snooze) reminders. It’s different! Don’t think that you can use Google Calendar or Remember the Milk to have the same feature!



Pestering: a killer feature

I am a nostalgic fan of the (imho) wonderful PingMe reminder web service, which unfortunately has been discontinued by Zemetic company last spring, due to overwhelming difficulties outlined in this blog post.

After PingMe shut down I had to look for a valid alternative among the many other free web reminder services. Apparently, this did seem a simple task, even because I was interested only in email reminders and I hadn’t other very sophisticated needs. Still I really missed a feature I can’t live without and that I have found only in PingMe service: the support for pestering reminder, which is a reminder repeatedly sent at given intervals until it is explicitily turn off (in PingMe this could be done in a very simple way by replying “done” or “ok” to the pestering email reminder).
For me pestering support is absolutely useful, since I am a very absent-minded person: I tend to forgive every to-do note just after few minutes I read it and therefore I really need nagging advices to stop only after having done the to-do job.


Why a DIY reminder?

Since, as I have already pointed out, I was not able to find any reminder service that supports pestering alarms, I have decided to build it by myself. My initial wish was to have a fully email-driven reminder system which would have allowed to create, edit and delete reminder entries directly by email message send as in PingMe and other reminder web services. On the other hand, after bailing out some other ideas, I have realized that the great facility of Google docs, even not allowing identical operating ways, has all I need to easily make a convenient personal email reminder system with pestering support and email integration:

  • a database to put and organize all reminder tasks (by a spreadsheet);
  • a way to interact with the database to stop pestering (by a form);
  • a procedure to check reminder deadlines and handle stop pestering commands (by some script triggers).

data visualization for two-way tables /1


introduction

Bar chart is in many cases the simplest and most effective way to visualize a discrete data set. But working on more than one data set, does it exist a graph which is better than the simple cluster histogram, at least in some cases?

I will try to answer to this question splitting my discussion in more than one post and introducing a different graph type in each of them.

By way of example it is convenient for me to look into the following table which has been already commented and discussed in some other professional sites. It shows the energy quantities (in quadrillions of BTU) consumed in US during 1995 for different sources and for different uses (approximations are mine from this scheme):