Archive for category Uncategorized
Strange times: Ice forming in unlikely places and melting where it shouldn’t
Posted by mark in Nature, Uncategorized on December 9, 2012
My flight yesterday from Minneapolis to Santiago got held up for de-icing. Being so near to the year-end solstice, the change in seasons from Minnesota to Chile could not be more dramatic—a swing of 45 degrees in solar angle relative to the ecliptic plan. So it’s out of snow (storming today back home) and into 80+ degrees and pure sun. : )
Things are wackier than I’d thought in regard to where one might expect to find ice nowadays. For example, who would have thought that water could freeze on Mercury? But that’s what NASA recently reported based on a shout out from their spacecraft Messenger, which detected polar hydrogen via neutron spectroscopy. See the details here. I enjoyed the quip by Sean C. Solomon, the principal investigator for Messenger, about there being enough ice to encase Washington, D.C., in a frozen block two and a half miles deep.* That might be what’s needed to cool down all the rhetoric about the fiscal cliff. 😉
Meanwhile the worries about the warming climate melting Earth’s icecaps just keep coming on. Concerned about contrails contributing to the greenhouse effect, the Washington Post is now demanding the Santa’s sleigh be grounded. Read this 12/4/12 blog and weep. : (
*On Closest Planet to the Sun, NASA Finds Lots of Ice, 11/29/12
The amazing persistence of biased scientific results—Popeye’s spinach found fraudulent
Posted by mark in science, Uncategorized on December 5, 2012
I recently completed a series of webinars on using graphical diagnostics to deal with bad experimental data.* The first thing I focused on was avoidance of confirmation bias – hearing what you want to hear, for example in the persistence of the possibilities of cold fusion. See more cases of confirmation bias in this detailing by Peter Bowditch in Australasian Science.
I came across another interesting example of the persistence of wished-for results in a review** of Samuel Arbesman’s new book on The Half-Life of Facts. It turns out that spinach really does not delivery the amount of iron that my mother always believed would make it worth us eating this horrible food. She was a child of the 1930’s, at which time it was widely believed that the edible (?) plant contained 35 milligrams of iron, a tremendous concentration, per serving. However, the actual value is 3.5 mg—the chemist who first analyzed it misplaced the decimal point when transcribing the data from his notebook in 1870! In 1937 this error was finally corrected, but my mom never got the memo, unfortunately for me and my six younger siblings. ; )
*“Real-Life DOE” presentation, posted here
** The Scientific Blind Spot by David A. Shaywitz in the 11/19/12 issue of Wall Street Journal
Time to lighten up on homework?
Posted by mark in pop, Uncategorized on October 21, 2012
The Wall Street Journal’s Market Watch this Friday posted the data shown in this chart. For the 11 countries shown** you can see why WSJ seconds the call by French President Hollande to ban all homework.
Students would party hearty but this laissez-faire approach will not fly with those blessed with ambitious parents. Nevertheless the call for less homework, fueled by new data from the National Center for Education Statistics, reinforces other studies going back at least a decade.
It will be interesting to see what emerges as a consensus for a the happy medium on amount of homework assigned. Four hours per night seems way too much, especially at the 8th grade level.
Meta-analysis of hundreds of studies done on the effects of homework shows that the evidence supporting the practice is, at best, modest. Homework seems to be most useful in high school and for subjects like math. At the elementary school level homework seems to be of marginal or no academic value.
– Malcolm Gladwell
*See the report here
**I took out Saudi Arabia, whose result of 34% below average, given 11% being assigned over 4 hours of homework per night, fell far below even these very off-putting predictions–an outlier statistically.
Acknowledgment: Thanks to Devan Govender for alerting me to this issue.
Rock on with algorithms?
Posted by mark in pop, Uncategorized on October 2, 2012
I started off my career as an experiment designer before the advent of cheap calculators. Paying $400 for an HP unit that (gasp!) did logarithms went far beyond my wherewithal in 1974. That was roughly the tuition for one college quarter at University of Minnesota if memory serves. I managed to cover that cost plus room and board by working 24 hours a week washing pots and pans at a hospital kitchen. Those were the days!
Calculating effects from the two-level factorial designs I did that summer as an intern at a chemical research lab required a lot of hand calculations—many numbers to add and subtract. Thankfully a fellow named Yates developed an algorithm after these experiments were invented in the 1930s. Following his directions one could tally things up and even do check sums without having to think much. That’s what algorithms do—provide a recipe for solving problems.
As an engineer I have a healthy respect for algorithms, but my wife, who works as a preschool teacher, thinks this is geeky. For example, I admired the nerdy professor in the TV show “Numbers” that aired a few years ago. But every time he expounded on some algorithm that ingeniously saw the pattern of a serial criminal, she just laughed. Ironically she is now hooked on a show called “Person of Interest” that is based on predictive policing, that is, using algorithms to calculate a crime to come. That scares me!
According to a new book by Christopher Steiner titled Automate This: How Algorithms Came to Rule Our World (see this Wall Street Journal review) all of us had best be on our guard against seemingly clever ways to systematically solve problems. It seems that the engineers, mathematicians, programmers and statisticians who come up with these numerical recipes invaded Wall Street. They became known as the “Quants”—dominating the way stocks now get traded.
The problem with all this (even I have to admit) is that these systematic approaches to things take all the fun out of making choices. Do we really want algorithms to pick our soul mates, invest our money, etcetera? I am up for algorithms like Yate’s that quickly solve mathematical problems. A good example of this is the first known algorithm recorded on clay tablets in 2500 B. C. that helped Sumerian traders divvy up a given amount of grain equally to a varying number of recipients. However when things become capricious with many unknowns that are unknowable being thrown into the mix, I’d rather make my own decisions guided by wise counsel.
There is an elephant in the room whenever it comes to discussing computer algorithms, particularly highly automated ones. Almost all such algorithms are inaccurate. They are inaccurate for many reasons, the most important of which is that human behavior is fickle. The inaccuracy could be shockingly high.
– Kaiser Fung, author of Numbers Rule Our World
I really shouldn’t bring this up, but do you suppose certain politician might be spending a lot of money on algorithmic solutions to how they can win election? Do these algorithms have any qualms about turning their protagonists into nabobs of negativism? I do not believe that an algorithm has any heart, unfortunately. An algorithm is like Honey Badger—it just don’t care.
Random thoughts
Posted by mark in Basic stats & math, design of experiments, Uncategorized on August 26, 2012
The latest issue of Wired magazine provides a great heads-up on random numbers by Jonathan Keats. Scrambling the order of runs is a key to good design of experiments (DOE)—this counteracts the influence of lurking variables, such as changing ambient conditions.
Designing an experiment is like gambling with the devil: only a random strategy can defeat all his betting systems.
— R.A. Fisher
Along those lines, I watched with interest when weather forecasts put Tampa at the bulls-eye of the projected track for Hurricane Isaac. My perverse thought was this might the best place to be, at least early on when the cone of uncertainty is widest.
In any case, one does best by expecting the unexpected. That gets me back to the topic of randomization, which turns out to be surprisingly hard to do considering the natural capriciousness of weather and life in general. When I first got going on DOE, I pulled numbered slips of paper out of my hard hat. Then a statistician suggested I go to a phone book and cull numbers from the last 4 digits from whatever page opened up haphazardly. Later I graduated to a table of random numbers (an oxymoron?). Nowadays I let my DOE software lay out the run order.
Check out how Conjuring Truly Random Numbers Just Got Easier, including the background by Keats on pioneering work in this field by British (1927) and American (1947) statisticians. Now the Australians have leap-frogged (kangarooed?) everyone, evidently, with a method that produces 5.7 billion “truly random” (how do they know?) values per second. Rad mon!
It’s the letter of the law: Stand down with Calibri
Posted by mark in Consumer behavior, Graphics, Uncategorized on August 17, 2012
Twenty years ago or so I cajoled the advertising rep from R&D Magazine into lending me a binder filled with several inches of ‘white papers’ of the publisher’s research on readership. Their data came primarily from A/B (split) testing—not very sophisticated but effective for simple comparisons. One question I resolved was whether to use serif or sans serif font. The research showed significant advantages to headlines being san serif, such as Arial font, and text in serif—for example, Times New Roman. I’ve stuck with that ever since,* except for the fonts themselves changing over to Calibri and Cambria—the defaults in current versions of Microsoft Office software.
However, now I am set back by this news from Wall Street Journal that Calibri comes up short—30 percent to be precise—versus Arial and other common fonts, at least so far as the State of Michigan is concerned. The inventor of Calibri, Lucas de Groot, justifies his type being smaller because of its high readability per square inch. Although this seems plausible to me, I would like to see the research supporting this assertion.
For an interesting detailing of fonts—serif versus san serif and neo-grotesque versus humanist—see this blog by Laurie Israel Think.
*For writings that will likely be read in printed form, that is. Having seen research like this recent study from the JOURNAL OF COGNITIVE PSYCHOLOGY, I believe that words written in a sans serif font provide a significant advantage for messages read on computer screens, such as blogs and email. Thus for these purposes I prefer using Calibri exclusively—ditto for presentations projected on screen, for example—using Powerpoint.
Polysci prof asks “Is Algebra Necessary”?
Posted by mark in pop, Uncategorized on July 29, 2012
I was appalled to see this titular question on the front of today’s (Sunday) New York Times opinion section. It came along with this sidebar quote:
There is no good reason to force students to master quadratic equations. Doing so holds them back.
That really riles me up, seeing as how these polynomials work so well for response surface methods (RSM) for process optimization. The author, Andrew Hacker–emeritus professor of political science at City University of New York, believes that, by making math mandatory, our educational system filters out talented scholars. As an alternative to hard-core number-crunching, he proposes the “exciting courses” in ‘citizen statistics’ such as the Consumer Price Index. His aim is “to treat mathematics as a liberal art, making it as accessible and welcoming as sculpture or ballet.”
I enjoy seeing statues and I admire the grace and athleticism of dancers; however, Hacker’s vision is for me dystopian. But so long as the educational system provides for a branching of those who like math versus the others who do not, then we get the best of all worlds. I agree–let’s not force algebra on those who abhor it.
A strange pink elephant — the Higgs boson
Posted by hank in science, Uncategorized on July 9, 2012
In our business we focus a lot of energy to convince experimenters they must conduct enough runs to develop the statistical power needed for detecting an effect of interest. What amazed me about the recent discovery of the Higgs boson is the sample size required to see this “strange pink elephant” as it’s described in the embedded explanatory video cartoon. The boffins of CERN took 40 million measurements per second for 20 years. These physics fellows cannot be topped for being persistent, tenacious, dogged and determined. Good for them and, I suppose, us.
“If the particle doesn’t exist, one in 3.5 million is the chance an experiment like the one announced would nevertheless come up with a result appearing to confirm it does exist.”
– Carl Bialik, ‘The Numbers Guy’ for Wall Street Journal explaining in his July 7-8 column the statistical meaning of CERN’s 5 sigma standard of certainty (see How to Be Sure You’ve Found a Higgs Boson).
Statisticians apply stylometry to identify authors and they invent algorithms that assess essays
Posted by mark in pop, Uncategorized on June 20, 2012
My colleague Tryg, who, like me, loves word play, drew my attention to this podcast* that explains how “By Their Words You Shall Know Them.” I teed it up on my smart phone and listened on my way to work yesterday—a fun way to pass my half hour commute into Minneapolis from my home in Stillwater, Minnesota. One thing that caught my ear was the early 1960s work by Harvard statistician Frederick Mosteller to pin down who wrote 12 of the 85 Federalist papers published under the pen name “Publius”. He and colleague David Wallace (University of Chicago) applied Bayes; theorem to attribute these writings to James Madison (as opposed to Alexander Hamilton). Mosteller also led the way to today’s reliance on statistics in sports by doing the first known academic analysis of baseball in 1946—concluding that luck rules even in a seven game World Series. He didn’t agree that, though the Cardinals beat his home town Red Sox, the best team actually won.
This analytical dissection of written words has come to be known as “stylometry”. As computing power increases and algorithms develop, writings are being put to the test. For example, see this New York Times Digital Domain column from earlier this month that details developments in ‘essay-scoring engines’. For now the students hold the upper hand on computer-based grading of papers—web-based essay mills can easily throw together fact-laden gibberish that fools the virtual professors. These are easily seen by teachers when they skim the results—check out some goofy passages passed along by Duke University professor Dan Ariely in this editorial for the Los Angeles Times .
The advent of spell-checking and grammar inspection in word processors has been a boon for writers. However, passing these tests does not necessarily lead to clear prose. When I started work as an engineer, the head of our process development group handed me a little booklet by Robert Gunning on “How to Take the Fog Out of Writing”. He advocated short, active sentences—not the passive, long and pedantic style I’d grown accustomed to from academia. See how your writing scores for fog using this online tool by Simon Bond. The quote below scored 20.86. This paragraph came back with a fog index of 9.152 (up to this clause to be precise!). Gunning’s score estimates the years of formal education needed to understand text on a first reading. Thus my writing supposedly can be understood by 10th grader. Draw your own conclusions on the readability of our founding fathers.
“As there is a degree of depravity in mankind which requires a certain degree of circumspection and distrust, so there are other qualities in human nature which justify a certain portion of esteem and confidence.”
– Madison, Federalist Papers #55, 346
*By online Slate magazine’s Lexicon Valley host Mike Vuolo
Irish Times says “serious issue settled” — Guinness does indeed travel badly
Posted by mark in Consumer behavior, Uncategorized on June 9, 2012
Lab Times author Thirsty O’Leary provides this summary of a scientific study by Liam Glynn, et al, that proves Guinness beer does not travel well. Some say it’s a conspiracy of the Irish—them drawing off the cream from the barrel. Although Guinness is not my cup of tea, I admire the work that went into this experiment. These zealots for zymurgy went all out! And, as those of use students ; ) of stats know, Guinness goes down well with quantitative research of this sort.*
“Each pint is like a child. You have to mind it through the entire process.”
— Fergal Murray, Guinness brew master
*See Guinnessometrics: Saving Science and Statistics With Beer