Global Warming

Hmm, it seems there is more out about global warming and the data still says the Earth is getting warmer. First, via here, a study finds the same basic ‘hockey stick’ graph using different methods. Being a math guy, I love this:
The sheer amount of computation, however, is daunting, involving heavy matrix algebra. Initial values [...]

Math and a new poem

Ok, I’m really just linking to a post by Krugman:
What I objected to in the mag article was the tendency to identify good math with good work. CAPM is a beautiful model; that doesn’t mean it’s right. The math of real business cycle models is much more elegant than that of New Keynesian models, let [...]

PhD

Well then. Today I submitted my thesis to the university, which means that I’m basically done with my PhD (there is a check of the pdf file I submitted only). Yay.
It works out that this weekend I’m going to Baltimore to celebrate a friend’s 40th birthday, which I can use as a celebration for me. [...]

Google understands i?

I think I used to know this, but forgot (I am old). Google has a built-in calculator and gives answers like:
e^(pi * i) = -1  and ln(-1) = 3.14159265 i
Yay, it likes imaginary stuff. It will also convert numbers into roman numerals:
2177 = MMCLXXVII
and will add in hexadecimals (among others–the 0x says that we’re looking at [...]

Vegetarianism is an eating disorder?

Time magazine has an article about this study on the association of eating disorders and being a vegetarian. Like most studies there are things you can argue with, such as:

Responses categorized as healthful weight-control behaviors included “exercised,” “ate more fruits and vegetables,” “ate less high-fat foods,” and “ate less sweets.” Less-extreme unhealthful weight-control behaviors included “fasted,” [...]

Millionaire mathematician

Hmm (via),
In 1999, a slight, unassuming man approached architects Brigitte Shim and Howard Sutcliffe with a whopping proposition: Build a house with curves, glass and a concert hall. No deadlines, no design restraints. The final cost: $24 million, nearly every penny the man had saved over 60-odd years.
…
The home’s owner is equally eccentric. Jim Stewart, who [...]

Cartoon Statistics

I got a card asking me to try the Manga Guide to Statistics (or at amazon). It actually doesn’t look too bad (I’ve only seen excerpts, so it’s a bit hard to tell) and it’s $20 ($13.57 at amazon) which is a very good selling point. I might actually get a copy to really see what [...]

The problem with schools and elitism

The Boston Globe has an article about the consolidation of schools. The idea of the governor is that larger schools will save money and give a better education, while the article tries to argue that neither is true. Besides the fact that I went to a consolidated school (ConVal in Peterborough, NH), I don’t know enough [...]

Random music? and a poem

So I decided to see if iTunes is close to random, but since I have 3104 songs this could take a while. So far it has played 44songs since I put them in. This is a vacation week, so I don’t feel like doing the work to figure out things. Still, so far no songs [...]

Square Root Day

Hmm, I almost missed square root day. I wouldn’t have minded too much, because it seems a bit fake to me–March 3, 2009 is 3/3/09 so the month and the day are both the square root of the year. The last real root day was 12/12/1728 which would have been a cube root day and [...]

Baye’s Rule

Since Baye’s Rule came up in the problem from xkcd that I linked to a couple posts ago, I thought I would put up a more basic problem that looks at it:
Suppose a disease is present in .1% of the population (so one in a 1000). A test for the disease is 99% accurate (so [...]

A math puzzle via xkcd

Not only is xkcd a great comic, but they also put up problems like this one (via here):
Sue and Bob take turns rolling a 6-sided die.  Once either person rolls a 6 the game is over.  Sue rolls first, if she doesn’t roll a 6, Bob rolls the die, if he doesn’t roll a 6, Sue [...]

Cost of textbooks

Via Kevin Drum (there are some interesting comments there), I went to see Andrew Gelman’s post about $150 statistics textbooks. Since I’m teaching introductory statistics, this is a timely post (in fact I’m supposed to give the text for a summer course by the end of the day–and I’m not even going to teach it). One of [...]

Math and security searches

Via this NY Times article, here’s an article by William Press on the math for the optimal strategy for things like airport searches (the article is free to look and uses only higher level undergraduate math). It’s first run through assumes that the government has some assigned probability that a person is a terrorist (where there [...]

No $Google notes

Drat, I was hoping the google dollar note would be coming out soon:
New Zimbabwean dollar bills will be equal in value to the old trillion-dollar notes. Six months ago the government dropped 10 zeros from the dollar.
This means the new dollar will be worth 10,000,000,000,000,000,000,000 (10^22) times a dollar from 6 months ago. Thus, without [...]

Numbers Stuff

The Numbers Guy has two posts that I find interesting:

the first wonders who was the most successful nation in the Olympics. He links to a WSJ article that ranks the countries that won a medal by a few categories. We find that The Bahamas won the most medals per capita and Zimbabwe won the most per [...]

The Antikythera Device and a Bit of Math

Via this article in the NY Times, I went to an article in Natureabout new information about the Antikythera device. The Antikythera device is a clockwork mechanism found in 1901 off Antikythera, Greece that was made somewhere around 100 BC. It was a very elaborate device that it worked on the Metonic calender (a 19 [...]

Cost of Global Warming

Paul Krugman has a post about the cost of global warming as a response to this articleby Bjorn Lomborg. He talks about the cost of uncertainty, linking to this paperby Martin Weitzman and a summary here. Here’s the idea:
It helps that Weitzman has a compelling story to tell: Climate change is fundamentally a problem about uncertainty. [...]

Mirrors and Perception

The NY Times has an article about mirrors. The first part is something I would expect:
In a report titled “Mirror, Mirror on the Wall: Enhancement in Self-Recognition,” which appears online in The Personality and Social Psychology Bulletin, Nicholas Epley and Erin Whitchurch described experiments in which people were asked to identify pictures of themselves amid [...]

Monty Hall and Other Number Stuff

Being a math guy I really should link to more math. Here’s a review of The Drunkard’s Walk by Leonard Mlodinow. It could be interesting if these couple examples are any indication:
Mlodinow learned the difficulty firsthand nearly 20 years ago when his doctor told him, out of the blue, that it was 99.9 percent certain that [...]