Archive for The God Delusion

a quincunx on NBC

Posted in Books, Kids, pictures, Statistics with tags , , , , , , , , , , on December 3, 2017 by xi'an

Through Five-Thirty-Eight, I became aware of a TV game call The Wall [so appropriate for Trumpian times!] that is essentially based on Galton’s quincunx! A huge [15m!] high version of Galton’s quincunx, with seven possible starting positions instead of one, which kills the whole point of the apparatus which is to demonstrate by simulation the proximity of the Binomial distribution to the limiting Normal (density) curve.

But the TV game has obvious no interest in the CLT, or in the Beta binomial posterior, only in a visible sequence of binary events that turn out increasing or decreasing the money “earned” by the player, the highest sums being unsurprisingly less likely. The only decision made by the player is to pick one of the seven starting points (meaning the outcome should behave like a weighted sum of seven Normals with drifted means depending on the probabilities of choosing these starting points). I found one blog entry analysing an “idiot” strategy of playing the game, but not the entire game. (Except for this entry on the older Plinko.) And Five-Thirty-Eight surprisingly does not get into the optimal strategies to play this game (maybe because there is none!). Five-Thirty-Eight also reproduces the apocryphal quote of Laplace not requiring this [God] hypothesis.

[Note: When looking for a picture of the Quincunx, I also found this desktop version! Which “allows you to visualize the order embedded in the chaos of randomness”, nothing less. And has even obtain a patent for this “visual aid that demonstrates [sic] a random walk and generates [re-sic] a bell curve distribution”…]

prayers and chi-square

Posted in Books, Kids, Statistics, University life with tags , , , , , , on November 25, 2014 by xi'an

One study I spotted in Richard Dawkins’ The God delusion this summer by the lake is a study of the (im)possible impact of prayer over patient’s recovery. As a coincidence, my daughter got this problem in her statistics class of last week (my translation):

1802 patients in 6 US hospitals have been divided into three groups. Members in group A was told that unspecified religious communities would pray for them nominally, while patients in groups B and C did not know if anyone prayed for them. Those in group B had communities praying for them while those in group C did not. After 14 days of prayer, the conditions of the patients were as follows:

  • out of 604 patients in group A, the condition of 249 had significantly worsened;
  • out of 601 patients in group B, the condition of 289 had significantly worsened;
  • out of 597 patients in group C, the condition of 293 had significantly worsened.

 Use a chi-square procedure to test the homogeneity between the three groups, a significant impact of prayers, and a placebo effect of prayer.

This may sound a wee bit weird for a school test, but she is in medical school after all so it is a good way to enforce rational thinking while learning about the chi-square test! (Answers: [even though the data is too sparse to clearly support a decision, esp. when using the chi-square test!] homogeneity and placebo effect are acceptable assumptions at level 5%, while the prayer effect is not [if barely].)

the intelligent-life lottery

Posted in Books, Kids with tags , , , , , , , on August 24, 2014 by xi'an

monkey at Amber FortIn a theme connected with one argument in Dawkins’ The God Delusion, The New York Time just published a piece on the 20th anniversary of the debate between Carl Sagan and Ernst Mayr about the likelihood of the apparition of intelligent life. While 20 years ago, there was very little evidence if any of the existence of Earth-like planets, the current estimate is about 40 billions… The argument against the high likelihood of other inhabited planets is that the appearance of life on Earth is an accumulation of unlikely events. This is where the paper goes off-road and into the ditch, in my opinion, as it makes the comparison of the emergence of intelligent (at the level of human) life to be “as likely as if a Powerball winner kept buying tickets and — round after round — hit a bigger jackpot each time”. The later having a very clearly defined probability of occurring. Since “the chance of winning the grand prize is about one in 175 million”. The paper does not tell where the assessment of this probability can be found for the emergence of human life and I very much doubt it can be justified. Given the myriad of different species found throughout the history of evolution on Earth, some of which evolved and many more which vanished, I indeed find it hard to believe that evolution towards higher intelligence is the result of a basically zero probability event. As to conceive that similar levels of intelligence do exist on other planets, it also seems more likely than not that life took on average the same span to appear and to evolve and thus that other inhabited planets are equally missing means to communicate across galaxies. Or that the signals they managed to send earlier than us have yet to reach us. Or Earth a long time after the last form of intelligent life will have vanished…

summer reads

Posted in Books, Travel with tags , , , , , , , , , , on August 23, 2014 by xi'an

wells3I had planned my summer read long in advance to have an Amazon shipment sent to my friend Natesh out of my Amazon associate slush funds. While in Boston and Maine, I read Richard Dawkins’ The God delusion, the fourth Kelly McCullough’s Fallen Blade novel, Blade reforged, the second Ancient Blades novel, unrelated to the above, A thief in the night, by David Chandler, and also the second Tad Williams’ Bobby Dollar novel, Happy Hour in HellThe God delusion is commented on another post.

Blade reforged is not a major novel, unsurprisingly for a fourth entry, but pleasant nonetheless, especially when reading in the shade of a pavilion on Revere Beach! The characters are mostly the same as previously and it could be that the story has (hopefully) come to an end, with (spoilers!) the evil ruler replaced by the hero’s significant other and his mystical weapons returned to him. A few loose ends and a central sword fight with a more than surprising victory, but a good summer read. Checking on Kelly McCullough’s website, I notice that two more novels are in the making….

Tad Williams’ second novel Happy Hour in Hell is much less enjoyable as the author was unable to keep up with the pace and tone of the highly imaginative first novel, full of witty and hard-boiled exchanges. The first novel introduced the (after-)life of a guardian angel in California, Doloriel (a.k.a. Bobby Dollar), with enough levels of political intrigue between Heaven and Hell and Earth and plots, pursuits, assassination attempts, etc., to make it a page-turner. This second novel sends Doloriel on a suicide mission to Hell… and the reader to a Hell of sorts where the damnation is one of eternal boredom! What made the first novel so original, namely the juxtaposition of the purpose of a guardian with his every-day terrestrial life, is lost. All we have there is a fantastic creature (from Heaven) transposed in another fantastic environment (Hell) and trying to survive without a proper guide book. The representation of Hell is not particularly enticing (!), even with acknowledged copies from Dante’s Inferno and Hieronymus Bosch’s paintings. There is a very low tolerance level to my reading of damned souls being tortured, dismembered, eaten or resuscitated, even when it gets to the hero’s turn. Add to that a continuation of the first book’s search for a particular feather. And an amazing amount of space dedicated to the characters’ meals. This makes for a very boring book. Even for a rainy day on a Maine lake! The depiction of the levels and inhabitants of Hell reminded me of another endless book by Tad Williams, Shadowmarch, where some characters end up in a subterranean semi-industrial structure, with a horde of demon-like creatures and no fun [for the reader!]. Ironically, the funniest part of reading Happy Hour in Hell was to do it after Dawkins’ as some reflections of the angel about the roles of Heaven and Hell (and religion) could have fitted well into The God delusion! (Too bad my Maine rental had Monty Python’s Holy Grail instead of The Life of Brian, as it would have made a perfect trilogy!)

Most sadly, David Chandler’s A thief in the night had exactly the same shortcomings as another book  I had previously read and maybe reviewed, even though I cannot trace the review or even remember the title of the book (!), and somewhat those of Tad Williams’ Happy Hour in Hell as well, that is, once again a subterranean adventure in a deserted mythical mega-structure that ends up being not deserted at all and even less plausible. I really had to be stuck on a beach or in an airport lounge to finish it! The points noted about Den of Thieves apply even more forcibly here, that is, very charicaturesque characters and a weak and predictable plot. With the addition of the unbearable underground hidden world… I think I should have re-read my own review before ordering this book.