Google is known to ask the following question in job interviews: In a country in which people only want boys every family continues to have children until they have a boy. If they have a girl, they have another child. If they have a boy, they stop. What is the proportion of boys to girls in the country?
Think you know the answer? If so, Steve Landsburg may be willing to bet you up to $5000. [more inside]
posted by gsteff
on Jan 1, 2011 -
"Normal" human pregnancies last 40 weeks, right? Well, no; they can vary quite a bit by the mother's race
, number of previous children
, family history of delivering early or late
, home state
, work habits
, and even the fetus' HLA type
. So where does that "40 week" thing come from? Oh, dear.
So check out this super-nerdy pregnancy statistics
website, from an engineer mom who is collecting data from the public
(see the raw data
and auto-generated graphs
, and read the FAQ about the survey, with more cool graphs
). Looking for day-by-day
probabilities on when that baby's due? This would be your stats table with daily prediction
(adjust dates at top of page as needed). Of course, you could always shut up your constantly inquiring relatives and friends another way
posted by Asparagirl
on Dec 16, 2010 -
Measure-theoretic probability: Why it should be learnt and how to get started.
The clickable chart of distribution relationships.
Just two of the interesting and informative probability resources I've learned about, along with countless other tidbits of information, from statistician John D. Cook
and his probability fact-of-the-day Twitter feed ProbFact
. John also has daily tip and fact Twitter feeds for Windows keyboard shortcuts
, regular expressions
, TeX and LaTeX
, algebra and number theory
, topology and geometry
, real and complex analysis
, and beginning tomorrow, computer science
posted by grouse
on Dec 5, 2010 -
Let's say you're me and you're in math class, and you're supposed to be learning about factoring. Trouble is, your teacher is too busy trying to convince you that factoring is a useful skill for the average person to know with real-world applications ranging from passing your state exams all the way to getting a higher SAT score and unfortunately does not have the time to show you why factoring is actually interesting. It's perfectly reasonable for you to get bored in this situation. So like any reasonable person, you start doodling. [more inside]
posted by ErWenn
on Dec 3, 2010 -
A Brief History of Mathematics
is a BBC series of ten fifteen-minute podcasts by Professor Marcus du Sautoy about the history of mathematics from Newton and Leibniz to Nicolas Bourbaki, the pseudonym of a group of French 20th Century mathematicians. Among those covered by Professor du Sautoy are Euler, Fourier and Poincaré. The podcasts also include short interviews with people such as Brian Eno and Roger Penrose.
posted by Kattullus
on Dec 1, 2010 -
"Michel de Montaigne, whose essays transformed Western consciousness and literature, was not capable of solving basic arithmetic problems. And most other people would not be able to do so either, if not for the invention of decimal notation by an unknown mathematician in India 1500 years ago.
" The Greatest Mathematical Discovery?
) a paper written for the US Dept. of Energy makes this assertion based in part on the work of Georges Ifrah. [via
] [more inside]
posted by jessamyn
on Aug 26, 2010 -
The 300th issue
of This Week's Finds in Mathematical Physics
will be the last. It is not an exaggeration to say that when John Baez
started publishing TWF in 1993, he invented the science blog, and an (academic) generation has now grown up reading his thoughts on higher category theory
, zeta functions
, quantum gravity
, crazy pictures of roots of polynomials
, science fiction
, and everything else that can loosely be called either "mathematical" or "physics."
Baez continues to blog actively at n-category cafe
and the associated nLab
(an intriguingly fermented commune of mathematicians, physicists, and philosophers.) He is now starting a new blog, Azimuth
, "centered around the theme of what scientists can do to help save the planet
posted by escabeche
on Aug 14, 2010 -
Interested in teaching yourself some statistics? Here is an excellent online and interactive statistics textbook
developed at UC Berkeley, and also used at CUNY, UCSC, SJSU, and Bard. Here is the syllabus
for the course at Berkeley. And here are some insightful reflections
from the professor on developing Berkeley's first fully approved online course.
posted by AceRock
on Aug 9, 2010 -
It has applications in Economics
, and is rooted in State Space Modeling
, which with Kalman Filtering
, breakdown [warning: long]
) was used in the Apollo program
. Dynamic Linear Models
are gaining in popularity. There exists an R package
, and both a short doc
and a really great (read: worth buying) book
(sorry, not a download, but here's chapter 2
) by Giovanni Petris
, Sonia Petrone
, and Patrizia Campagnoli with its own little website
posted by JoeXIII007
on Jul 30, 2010 -
Math Is No Match for Locust Swarms.
"Mathematicians have now figured out the dynamics that drive locusts across the landscape, devastating everything underfoot — and the math says people will never be able to predict where the little buggers will go.
The new analysis, reported in an upcoming issue of Physical Review E, suggests that random factors accumulate and influence how swarming locusts collectively decide to change course.
“These swarms are driven by intrinsic dynamics,” says team member Iain Couzin, a biologist at Princeton University. “In all practical terms, predicting when a swarm is going to change direction is going to be impossible." More information here
posted by Fizz
on Jul 27, 2010 -
If politicians were mathematicians.
"I would like to suggest two systems for parliamentary votes, one that would weaken the party system but without killing it off entirely, and one that would protect large minorities. Neither has the slightest chance of being adopted, because they are both too complicated to be taken seriously. But mathematicians wouldn’t find them complicated at all — hence the title of this post." Fields medalist Tim Gowers messes around with political axioms.
posted by escabeche
on May 12, 2010 -
A generating function is a way to keep track of a lot of related numbers all at once... The study of generating functions is an art and a science known as 'generatingfunctionology,'
and its bible is free for all to download. [more inside]
posted by kaibutsu
on Apr 22, 2010 -
's Magnetic sculptures
: "These forms are created with cylinder magnets, spherical magnets, and ball bearings. Magnetism is the only thing holding the forms together. They are fairly fragile and picking them up will likely crush them. All of the forms I created were variations of the 12 sided dodecahedron. This particular platonic solid seems to be the form the magnets are happiest with." [via
posted by dhruva
on Apr 14, 2010 -
is a set of thirteen surveys in varied topics in mathematics, nicely produced with video, text, and interactive Flash gadgets for each of the topics.
posted by Wolfdog
on Apr 14, 2010 -
Trigonometric Delights. This book is neither a textbook of trigonometry—of which there are many—nor a comprehensive history of the subject, of which there is almost none. It is an attempt to present selected topics in trigonometry from a historic point of view and to show their relevance to other sciences. It grew out of my love affair with the subject, but also out of my frustration at the way it is being taught in our colleges.
posted by Wolfdog
on Mar 24, 2010 -