Stats Made Easy

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2009-06-25T11:25:00.000-07:00

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Political science (?) based on happenstance regression

2009-05-11T11:52:00.000-07:00

My daughter Carrie, a junior at University of Minnesota -- majoring in political science, asked me to look over a paper she wrote last week for her quantitative-analysis class. Her assignment was to test “the theory that Christian religiosity, measured through church attendance, affected the outcome of the 2004 presidential election” (Bush over Kerry). Carrie considered many other variables that could logically have influenced voting decisions before settling on two alternative factors – per-capita income, and level of education.

As I’d expected, her regression analysis (using the SPSS software) showed a positive correlation of “frequent church goers” voting for Bush (0.166 R^2) and negative for “population with college degree or higher” (0.293). However, the highest correlation was seen with per-capita income, which surprised me by being negative – the more the voter earned, the more likely they were to NOT vote for Bush. I always thought that the Republicans were the party of the rich. But from this data one must conclude that they mainly appeal to poor, less-educated church-goers!

I don’t give too much credence to any of this – mainly due to my great skepticism of using statistics to dissect historical data and generate inferences on cause and effect relationships. However, it makes me curious as to the driving forces of today’s party politics in the USA. That’s about all I figure that regression of happenstance data really offers – some food for thought that may lead to more rigorous investigation.

Awesome demonstration of design of experiments

2009-04-27T17:05:00.000-07:00

The engineering students at South Dakota School of Mines and Technology really do rock. Where else could one present a class on statistics until 8:30 pm on a Friday night and continue it less than 12 hours later – early on a Saturday morning?

Our workshop on design of experiments (DOE) finished with a spirited competition of paper helicopters.* The winner was Team Awesome: Kayla Rithmiller, MacKenzie Trask and Samantha Johnson (pictured from left to right). They scored highest on the basis of flight time and accuracy. You can see their ‘copter spinning to another precise landing in their confirmation run.

Congratulations to Team Awesome and all the SDSM&T students who devoted their free time to learning DOE and demonstrating this newly-gained knowledge via well-planned experiments on the helicopter exercise. I predict that they all will go far!

*See details on this DOE exercise in the September 2004 Stat-Teaser article on Playing with Paper Helicopters.

Technology facilitates building a stronger database on blood pressure and other medical measurements

2009-04-20T16:24:00.000-07:00

Some years ago my wife was diagnosed with high blood pressure (hypertension). This necessitated regular measurements with an instrument called a sphygmomanometer, which took me a long while to master for spelling and pronunciation. Being a chemical engineer helped – we used manometers to track barometric pressure. The hard part is the “sphygmo” – a Greek word meaning to throb or pulse. However, it works nicely for blood pressure!

Blood pressure measurements via the mercury gravity sphygmomanometer are still considered to be “gold standard.” Nevertheless, electronic devices are far easier to use and affordable for home use. To help my wife keep track of blood pressure, I bought one made by Panasonic. This came in handy when I developed heart problems of my own – chronicled in my article “How DOE Saved My Life and Made it Worth Living” in the June 2008, Stat-Teaser.

This week’s CRNtech brought news of a Digital Blood Pressure Check via an inexpensive (less than $100) device that connects via USB to a PC for capturing results. This data can then be uploaded to Microsoft’s HeathVault. From there you can enable care givers to watch for statistical trends.

My guess is that by repeated measurements over time, facilitated by this do-it-yourself system, medical professionals would get a far more precise assessment of hypertension. This may be the answer to Blood Pressure Variability: The Challenge of Variation – an issue recognized in this recent publication of the American Journal of Hypertension (2008, 21 3–4).

“It is therefore practically impossible for a clinician to know whether he is changing a drug or dose in response to chance variation in blood pressure or true changes in the underlying mean blood pressure.”
-- Tom P Marshall, Department of Public Health and Epidemiology, University of Birmingham

TV detectives stumble over odds of matching birthdays

2009-04-12T13:36:00.000-07:00

Ever since his glory days as the laid-back Hawaiian detective “Magnum PI” I’ve always been a fan of actor Tom Selleck. Now he’s back on television as a moody police chief named Jesse Stone – a character based on a series of mystery novels written by Robert Parker. In the latest installment of the TV franchise (the first one not based directly on one of Parker’s books) Stone searches for a stolen baby thought to be living with the thief in his small Massachusetts’ town. All they know is the birthday and approximate age. One child comes up as a match, but the deputy cautions that it only takes 22 people to get two with the same birthday.

This birthday paradox provides some fun for teachers of statistics who have large enough classes to make a match likely: Simulate the possible outcomes with this fun applet by Stanford Professor Susan Holmes. However, the odds of matching an exact birthday are far lower – it takes 252 to achieve a 50% probability. These statistics are detailed by this Wikipedia article -- see the graphical comparison of the cumulative probabilities.

So I think the odds were fairly high that Chief Stone's hunch about the baby-snatcher was a good one -- simply based on the birthday of the child being a match. In any case, amazing coincidences are standard for novels, movies and television. The writers operate in a world where chance takes a back seat to drama. Thank goodness for that -- real statistics tend to be a bit boring for entertainment purposes.

PS. The photo is one of my all-time favorites from the family album -- it's my son Hank, who helps me with this blog. The Anderson clan now is up to 9 counting those who've married in. So far none of us share a birthday.

The science of “guesstimation”

2009-04-05T10:10:00.000-07:00

The latest National Geographic Science column on Mind Games shows a jar of jelly beans (presumably provided by the Easter bunny) and it offers a formula for estimating the number:

1. Count the jars radius (r) in beans. (This is hard to see due to the angle of the picture, but let’s say r equals 5.)
2. Estimate the height (h) in beans. (I can count this fairly easily from the photo – h equals 35.)
3. The volume (V) in beans is: V = 3 h r^2, where the constant 3 is a round-off on the circular constant pi. (So I estimate the beans in the National Geographic jar number 3x35x5^2, or 3x35x25 – the product of which is 2,625.)

The scientific, calculated estimate I made (2,625) for the count of jelly beans came a lot closer than my initial guess of ten thousand: The answer is 4,466. Going to all this effort might be worth it if you come across a bean-counting contest with a prize worth taxing your math skills.

Meanwhile, two professors at Old Dominion University in Virginia, one a mathematician (John Adam) and the other a physicist (Lawrence Weinstein), have teamed up to provide a primer on Guesstimation: Solving the World’s Problems on the Back of a Cocktail Napkin. As the publisher Princeton University Press says: “The ability to estimate is an important skill in daily life.”

As the father of five, I frequently was asked to help with math problems. First I’d ask that the student (my kid) work out a bottom-line number. Then I’d suggest they do a “reality check” by estimating the answer to at least the order of magnitude. That often sent them back to the beginning of the problem due to their first answer being so obviously wrong. The way facts and figures get thrown around the airwaves and internet nowadays it’s more important than ever to do reality checks.

I’ll bet this new book will be very helpful to equip reality checkers with the tools they need to achieve more accuracy. I learned about Guesstimation from its review in the March 31st New York Times. The Times article provides an interesting test of estimating ability: How many times does the American teenager say “like”? I heard this much more from my three daughters than my two sons, thus I hypothesize that there’s a gender bias. I’d hear this so word so over-used –- at least, like, once per sentence –- that I’d start counting them aloud, thus creating a great deal of aggravation for my teenager. I suppose the work “like” might come out ten times a minute and one hundred times per conversation. So I’m going to say a thousand “likes” per day could be in the realm of possibility. However, some teenagers are not afflicted by this word termite. My guess is ten thousand “likes” per year per teenager. To learn the answer, take this eight-question test of your estimation abilities.

Phenology -- the study of the timing of natural events

2009-03-27T18:18:00.000-07:00

Not to be confused with phrenology (measuring ones skull to assess character and intelligence -- both of which appear lacking in the subject pictured), the scientific discipline of phenology provides valuable barometers of climate change by its observation of seasonal natural events, for example --the dates that daffodils bloom near Cambridge, England. A chart on this is featured in the latest National Geographic alert on the environment. I wondered about the validity of the upward trend line superimposed on a broad scatter of data. However after seeing this presentation by Tim Sparks of the UK Phenology Network I am convinced: Flowers are definitely blooming earlier nowadays.

Here are upper Midwest USA phenological observations made for this month of March by the University of Wisconsin in Green Bay. It’s latest entry details the record flooding along the border of Minnesota and North Dakota – a disaster in the making. A bit cheerier is the news of someone sighting the first blooming of Symplocarpus foetidus (skunk cabbage). Whoopee!

Anyways, all this is an excuse for me to upload a photo I took last week along the Natchez Trace in Mississippi while on spring break last week. I do not know the identity of the plant in the foreground, but it caught my attention -- especially with the wonderful profusion of blooming azealas as a backdrop.

I did see the first robin in our front yard last week -- a sure sign that spring will come soon -- perhaps after the major snowstorm forecast for early next week.

Nearly 90% of cardiologist-approved heart therapies are not supported by high-quality scientific testing

2009-03-21T19:21:00.000-07:00

Recently the Wall Street Journal reported that a Study Questions Evidence Behind Heart Therapies -- specifically by this alarming statistic: “Just 11% of more than 2,700 recommendations approved by cardiologists for treating heart patients are supported by high-quality scientific testing.” It seems that the vast majority of prescribed treatments remain unratified by multiple randomized clinical trials – the highest level of evidence according to guidelines issued jointly by the American College of Cardiology and the American Heart Association.

I am caught up in this personally due to having had one heart attack some years ago. Ever since then I’ve been working hard to avoid a second one. My daily aspirin is strongly supported by scientific study, but it’s not very sure that I should be keeping on with the platelet inhibitor Clodiprogel (Plavix™, Bristol-Meyers Squibb/Sanofi Pharmaceuticals) prescribed after getting my clogged artery stented. I have to credit my cardiologist though – he is utterly impartial on the Clodiprogel – I cannot get any signal – pro or con. What can he say? As pointed out in this related article by US News & World Report no clinical trials exist beyond about one year (even that time is a bit vague!) of the heart surgery.

So as not to let all this cause me too much stress (possibly bad for the heart, but not strongly supported by solid scientific study) I picked up on this promising therapy – waltzing as a form of cardio-exercise. Evidently this works as well as trudging the treadmill and the dancing leads to a better quality of life as measured by the Minnesota Living With Heart Failure Questionnaire.* I note that the subjects were selected at random – that’s good, but “the study was not blinded, neither to the investigators nor to the patients.” Obviously it would not do to waltz blindly along, no matter how blissful that might be – until one hits the wall!

*I’d be skeptical if this weren’t based on Minnesota standards, that is, bitter cold, biting insects and so forth. ;)

Basketball players fail to cash in on free throws

2009-03-15T18:07:00.000-07:00

Tonight the NCAA filled out their 65-team* bracket for their annual Division I basketball championship. The quality of basketball will no doubt be better than ever, at least since 1995 when Kevin Garnett broke barriers by jumping directly from high school to the Minnesota Timberwolves. That really provides no excuse though for what Larry Wright, and adjunct professor of statistics at Columbia, says is a “mind boggling” lack of improvement in the rate at which college players make free throws. In this article by the New York Times, John Branch reports that in 1965 NCAA teams shot 69 percent. This year they cashed in from the 15 foot charity stripe at a rate of only 68.8 percent.

Some athletic endeavors leap ahead due to an innovation in technique, such as the Fosbury Flop in high jumping or skating on cross country skis. I wonder why more players don’t throw up free throws underhanded like Rick Barry did as depicted by this NBA website on The Art of the Free Throw. His 90 percent rate set the NBA bar when he retired.

I saw an interesting shooting variation at the halftime of a Timberwolves game a few weeks ago. They gave a fan one shot from half court to win a million dollars. The contestant was an older fellow who seemingly had no chance throw a basketball that far. However, he succeeded on distance by flinging it backward over his head, an approach used by this more accurate fan who won a car by sinking the 47-foot shot shown here.

It would be interesting to experiment with an accomplished basketball player to see how their shooting percentage would vary facing forward versus backward from the free-throw line. Surely the success rate would fall precipitously.** Actually, that might make things a lot more interesting – even the seemingly static 69 percent rate is too boringly accurate.

*One aspect of this “March Madness” is that it commences with a “play-in” game that makes one team the absolute loser!

**An exception might be 41 percent free thrower Ben Wallace seen missing the iron completely in this video . He should do the same as the fans watching him at the line -- don't look.

Detecting outliers graphically

2009-03-06T07:42:00.000-08:00

My son Hank, 'blogmeister' of StatsMadeEasy, just forwarded me this cartoon from Randall Munroe's blog xkcd. It dovetails nicely with my presentation to the ASQ Lean Six Sigma Conference this week titled "Friend or Foe? How to Use Graphical Diagnostics for Scoping Out Discrepant Data."*

As I am wont to do, I started my talk with a humorous anecdote on the topic. This is a story on seeking something out using visual clues. It's a matter of being on guard for something unusual like Nassim Taleb's Black Swan but being a Minnesotan my thinking differs a bit on what's distinctive.

"A fellow borrowed a neighbor’s fishing car** to sneak in some last-minute anniversary gift shopping at Mall of America (MOA) without his wife knowing. After wandering the vast hallways of MOA for a long period of time, he found just the thing. However, by then he’d forgotten where the car was and even what it looked like. All he could think of to tell the security staff was that the front right tire did not have a hub cap. After a thorough search the car was located. However, it would have been easier for the MOA staff if the fellow had thought to mention that the car had a red canoe strapped to the roof! "

*For the basis of my talk, see this manuscript.
**Fyi Minnesotans generally keep two spare automobiles -- a 'winter beater' that stands up to all the snow and road slop, plus an old 'fishing car' that can be kept at the ready with rods and all (and allowed to get stinky with fish and bait).

Statistics on education and education on statistics

2009-02-21T11:16:00.000-08:00

“Armed with a bevy of State testing data” our local school district’s Superintendent dispelled the notion that Minnesota charter schools provide a superior education. Charter schools are publicly funded, but they are run by independent boards. Their enrollment has doubled in the last 5 years, thus inciting battles of statistics like the one presented by the Superintendent this week. His main point was that published assessments do not account for the impact of special education, "at-risk" and other students that do not attend the particular charter school in our area. (To be fair to the ideal of charter schools, some actually provide for students with particular needs that would otherwise get lost in the shuffle.)

In the interest of helping the general public sort out the endless conflict of statistics by opposing groups like this, the Union College Academy for Lifelong Learning (UCALL) in Schenectady, New York invited an illustrious faculty, including Gerald Hahn – formerly statistician emeritus from General Electric, to teach a course “Numbers in Life.” This 10 hour presentation was really all about statistical literacy, but ironically the course coordinator advised that the word “statistics” in the course title would be a turn-off. That tells it all: How can people be educated a on a subject that must not be named (like the evildoer in Harry Potter)?

To the everlasting credit of Hahn and his fellow teachers, they gave “Numbers in Everyday Life” the old college try. Here are some of the course take-aways published in the February AmStat News (the parenthetical comments are my own):
-- Always ask who is taking/reporting the numbers and how they obtained.
-- Be wary of advocate’s numbers (such as a glowing report on a drug study sponsored by the manufacturer).
-- Remember that the news media seek surprising numbers.
-- Appreciate limitations of observational studies and differentiate correlation from causation.
-- Controlled experimentation (the forte of my company Stat-Ease) is the gold standard.

By the way, you’d best be wary of how I cherry-picked these take-aways to support the cause for design of experiments. Actually, this was one of the take-aways that I conveniently omitted (“cherry-picking”). ;) See the entire AmStat story posted via the YUDU epublishing initiative.

“One of the greatest contributions of statistical thinking… is design of experiments.” - Gerald Hahn

How to arrest what’s-his-name’s forgetting curve

2009-02-15T16:18:00.000-08:00

I forget how I first heard about the Ebbinghaus Forgetting Curve (it escapes me!) but it describes very well what I’ve observed when teaching statistics – a very rapid loss of knowledge – possibly as fast as 50 percent per day. However, it's been found that by repeated review and practice, details can be remembered for a much longer period of time. That’s why hands-on workshops can be so effective, as opposed to an academic lecture.

For example, I doubt that by noon I’d have been capable of recalling half of what I learned from an 8 AM organic chemistry lecture back in college. Ebbinghaus’s original forgetting curve probably fit my inability to remember chemical formulas. To make matters worse, my notes trailed off every few lines as I nodded off from all the boring details. That was not good, because the chem prof worked completely by lecture – no reference text. There was no chance of getting a ‘re-do’ on any of the presentations – no re-course so to speak (pun intended). Thus my performance on the final exam left much to be desired (at least I passed).

The lesson here is that reviews can be vital for remembering – repetition is the key to recall. Based on recall experiments (for example, the little know fact that Rudyard Kipling invented snow golf), researchers recently discovered the optimal intervals for repeating study sessions. This depends on how long a person wants to remember things. College students hoping to remember information just long enough for the semester-ending final should space study sessions every week apart may be ideal. However, to recall the details a year later a spacing of some months may be far better.

“To put it simply, if you want to know the optimal distribution of your study time, you need to decide how long you wish to remember something.”
-- From Spacing Effects in Learning by Nicholas J. Cepeda, Edward Vul, Doug Rohrer, John T. Wixted, and Harold Pashler

If you are determined to remember stuff, consider investing $35 in a flash-card program called FullRecall that promises to “help you memorize the knowledge for lifelong periods with the minimum time investment.” Its neural network converges on the user’s forgetting curve to schedule reviews just in time –i.e., when one gets close to forgetting a detail they hoped to remember.

PS. When I mentioned this blog on memory to my son, he recalled that a fellow named Pimsleur developed a graduated-interval recall system that’s now used for learning languages. In a 1967 publication titled A Memory Schedule, this Ohio State University professor observed that “the process of forgetting begins at once and proceeds very rapidly. If the student is reminded of the word before he has completely forgotten it, his chances of remembering will increase. After each such recall, it will take him longer and longer to forget the word again. Thus, a small number of recalls, if properly spaced, can bring about retention over a long period."

PPS. By reading the PS above, you just added some length to your recall of how repetition enhances memory. Good for you!

Feeling belittled? Cut off relations with short people!

2009-02-08T15:20:00.000-08:00

In July of 2007 The New York Times reported an amazing study on obesity by Harvard Medical School. Based on a statistical analysis of a large social network – over twelve thousand people followed for over thirty years, it concluded that a person’s chances of becoming obese nearly tripled when a close friend got fat (or to put it more nicely: “gravity challenged”). Apparently this effect works at a distance, thus a parent like me who just sent a child off to college can anticipate a pile of pounds from the dreaded “freshman fifteen.” Hey – that’s just not fair for one who’s already fighting a battle of the bulge! Also, I worry about getting connected up to wide-bodied people via LinkedIn and Facebook. I’ve noticed that whenever I start surfing these nets I start munching on Twinkies and other bad foodstuffs. This is not good!

Meanwhile, this bulletin from Yale University (might there be a rivalry between this school and Harvard?) counters with a Study [that] Contradicts Earlier Reports That Some Health Issues Are ‘Contagious’ Among Friends. Using similar statistical techniques as the one done on obesity in social networks the Yale researchers discovered that an individual’s height increased by 20 percent of a close friend's tallness. Therefore I conclude that by spending equal time emailing my beanpole friend and another buddy who inherited a more roomy body type then things will balance out weight-wise on a per height basis.

Now that’s how you can put stats to work with just a little creativity.

Decimal place makes all the difference

2009-01-25T09:23:00.000-08:00

I presented a world-wide webinar Wednesday on "An Introduction to Mixture Design for Optimal Formulations" (posted with prior Stat-Ease webinars). As an ice breaker I described the view from my desk of downtown Minneapolis cloaked in a fog of frozen water crystals. One of the participants, our new value-added reseller Peter Trogos of Boston Software Group, expressed curiosity as to how Minnesotans can stand living in our Nation's icebox. It is hard to explain, but here's an example of what works for me -- embracing the elements.

I dressed up for a walk yesterday and my wife Karen got very alarmed. She misread our outdoor digital thermometer as -13 degrees, but I could see it was only -1.3 degrees. The placement of a decimal makes all the difference!

For my fortitude in walking no matter what the elements (like the proverbial postman) I was rewarded with this vista of the soccer field adjoining a nearby preschool. It was fun to think of upcoming days in Spring when it will be filled with energetic kids!

However, I enjoy the solitude of this frozen season, when only the conifers and hardy birds (and manic Minnesotans) remain active.

"It was January and cold in Minnesota, which was redundant."

-- Garrison Keillor as Guy Noir in the 1/24/09 radio broadcast of A Prairie Home Companion

Paperwork reduction?

2009-01-24T15:37:00.000-08:00

I've just completed my first year of high-deductible medical insurance coupled with a health savings account (HSA). I like this relatively new option very much. However, it requires yet another form to be submitted to the Internal Revenue Service (IRS 8889). I printed this out yesterday. It seemed complete, but then one last page spit out with only this paperwork reduction notice -- nothing else on either side. Have you ever felt like crying and laughing at the same time? Anyways, I feel better now after processing this piece of paper with the IRS paperwork reduction notice. You can see where I put stuff like this -- a machine that makes a very satisfactory grinding noise, which saves me gnashing my teeth.

Which of these is the winter weather outlier?

2009-01-14T14:36:00.000-08:00

International (aka “Frostbite”) Falls reported a record low of 42 below Fahrenheit the other day. Would statisticians deem this an outlier? I think not – just another notch on the low end of the normal curve of temperature in this northern Minnesota city.

On the other hand, this morning I came across this pictured vehicle from Florida. That is much more unusual in the dead of Minnesota winter. You may not resolve the license plate in the photo, but here are a couple of clues that the driver is not a Minnesotan:
-- They did not brush off the snow from the rear window – only ran the wipers.
-- They are tailgating on the exit ramp to Interstate 694 on a day of extreme cold when black ice* makes the roads extremely slippery.

Given these unsafe practices, I predict that this outlying Floridian car will soon be off the roads and we will be back to our normal distribution of Minnesotan and Wisconsites (don't get me going on them!).

PS. Here’s a little poem that just came through in an email circulating around these parts (author unknown):

The weather here is wonderful
So I guess I'll hang around
I could never leave Minnesota
'Cause I'm frozen to the ground!

*If you do not know about black ice, consider yourself fortunate. It’s a phenomenon that occurs only in below-zero cold: The water resulting from the internal combustion engine freezes when the exhaust hits the road. This ice cannot be seen – hence the designation of it being “black.”

The MAD statistics for overkill

2009-01-11T17:33:00.000-08:00

Over Christmas vacation I took a tour of the Titan Missile Museum south of Tucson. There, seeing this moth-balled intercontinental ballistic missile (ICBM) under glass, visitors like me can relive the days when it seemed that nuclear Armageddon could occur at any time. I remember practicing duck and cover drills in grade school during the Cuban Missile Crisis. The exhibit I found most interesting from a statistical standpoint was a detailing of how many missiles the US military planned to launch in order to fulfill the doctrine of mutually assured destruction (MAD). They called this “overkill.”

“The reliability of the first 2 ICBM’s, Atlas and Titan, were so low the military determined they would need at least 4 ICBM’s to hit one target with the assumption of only a 70 percent chance of target strike success.”
-- Len Losik (MilsatMagazine “Military Satellites and Rockets—No More Failures!")

This MAD overkill boggles my mind by its macabre calculations of deathly probabilities.

PS. In my research I came across these intriguing just-published memoirs by General Glenn Kent and his “Thinking About America’s Defense” (made available as a public service by the RAND Corporation).

Number smiths gain top three spots for having the best occupations

2009-01-06T18:57:00.000-08:00

Today’s Wall Street Journal article on Doing Math to Find the Good Jobs reports that the top three professions are mathematician, actuary and statistician! The perpetrator of this outrageous claim is Les Krantz, author of the “Jobs Rated Almanac.” You can infer what floats his boat by comparing these three ivory tower jobs to the down and dirty ones he rated as the absolute worst: lumberjack, dairy farmer and taxi driver.

So it seems that this caps the revenge of the nerds. However, I am not sure what to conclude from a school chum who went on to become an actuary, made a mint in investments on the side and then retired early to become a dairy farmer. I suspect that many math mavens secretly desire being outdoors chopping trees rather than crunching numbers in an office.

Nevertheless, maybe it’s best for those of us that can do the calculations to resist acting upon our daydreaming during the deadly dull parts. For example, when I rev up my little chain saw things often get quickly out of control, such as the time I took it up a ladder to cut off a branch and while leaning at a particularly dangerous angle got stung viciously by a wickedly large wasp. At times like this one must be thankful for a job involving numbers that can be done despite being temporarily incapacitated.

Minneapolis most literate: Readers of the purple prose?

2008-12-26T07:05:00.000-08:00

Minneapolis tops the list of America's most literate cities according to this ranking by Dr. John W. Miller, president of Central Connecticut State University. His study focused on six indicators, including the number of libraries and bookstores. Although rankings like these are not very precise, it seems sensible to read often when residing in regions of the country where for long periods one dare not wander out the house due to extreme cold (Minneapolis) or unrelenting rain (such as Seattle, who tied for first in CSU's study).

I love to read in any season -- snug as a bug in a rug before the fireplace in our family room, or slacking off in the hammock out back on a sunny summer eve. In either place the ambiance is enhanced by our Golden Retriever Penny laying at or under my feet. A guilty pleasure of mine is to stoop occasionally to reading pulp fiction. For example, if the mood for adventure strikes, I may dip into a great collection of classic (an oxymoron?) western escapism by author Zane Grey, which I inherited from my wife's grandfather. It includes "Riders of the Purple Sage" -- his best known novel.

However, the book I'd put head and shoulders (plus a 10-gallon cowboy hat) above the purple prose of Grey is Owen Wister's ground-breaking novel The Virginian available in hypertext from The American Studies Programs at The University of Virginia. I love the title of Chapter 2: "When you call me that, Smile!" To set the mood for reading, here's a photo I took yesterday in the Saguaro National Park outside Tucson, Arizona after flying down yesterday to escape the snow and cold and overdose of Christmas back home in Minnesota.

Trying to remember what the prof taught in stats? A few Zzzs may help!

2008-12-20T12:11:00.000-08:00

Sorry, I must have been napping because I just now got around to the May issue of Scientific American which reported that even a six-minute snooze boosts recall. The benefits of sleep for enhancing memory are well known, but how quickly doe s it occur? Olaf Lahl, a psychology professor at the University of Dusselfdorf, gave subjects at his sleep lab two minutes to memorize 30 words. An hour later, after playing solitaire the whole time, the average subject recalled under 7 words. A short nap raised this above 8, while a longer, deeper sleep increased the average recall to more than 9 words. This article by the London Telegraph relays a theory by another sleep researcher Dr Robert Stickgold, from Harvard University. He thinks that “just before sleep, the brain ‘replays’ recent events, producing dreamlike sensations and ‘crazy’ thoughts.” Stickgold speculates that the brain sifts through newly entered material in a period of “thought marshalling” which may be crucial for recall.

I’ve always been a great believer in napping for as short a time as possible – just long enough to actually fall asleep, which takes me about 10 minutes. Then I drink a cup of coffee, and off I go again for many hours. I always thought of this as a “power nap.” The Wikipedia details a number of variations on this: cat-nap (same as power nap, but for slackers!), caffeine nap (drink coffee before laying down!) and NASA nap (good if you are an astronaut!).

The NASA findings favoring short sleeps for thier workers gained the notice of some employers, according to this ABC News report. As co-Director of Stat-Ease, I don’t like this idea very much. Once I literally stumbled across one of our summer programmers laid out on the office floor taking a snooze. Maybe I should be more open-minded about such behavior, but my name goes on the pay checks and I hate to think of getting no work per hour. That is not a good productivity statistic!

Search for extraterrestrial intelligence (SETI)

2008-12-14T14:54:00.000-08:00

Last month I enjoyed a visit to the Arecibo Observatory in Puerto Rico (pictured). I found the view as astounding as I’d thought from seeing it featured in the movies GoldenEye (James Bond) and Contact. In this latter film Jodie Foster starred as a character that author Carl based on Jill Tartar. Tarter is director of the center for research at SETI (Search for Extraterrestrial Intelligence) Institute in Mountain View. Evidently the future of SETI lies in arrays of telescopes, not a big dish like Arecibo, which will be closed down in few years according to their visitor center information.

After my visit to Arecibo I saw this CNN television feature on Tartar. She touted SETI’s new array of 350 steerable dish antennas built with the help of a $25 million endowment from Microsoft co-founder Paul Allen. See this fact sheet for details on progress so far and the goal for the Allen Telescope.

Do intelligent beings live outside our planetary system? Many people imagine so, for example in the movie The Day the Earth Stood Still that premiered this week (a remake of the 1950's classic). The brilliant physicist Enrico Fermi also felt sure ET must be out there, but if so, why hadn’t we seen them yet? This became know as the Fermi paradox. Later Frank Drake formulated an equation, which Sagan used for an optimistic view on the possibility of ETI. Author Michael Crichton (Jurassic Park, etc), recently departed, did not consider this calculation very scientific as noted in this blog by statistician William Briggs, which delves deeply into the whole controversy whether it's even worth speculating about extraterrestial intelligence.

I think it's not worth arguing about, but I am in favor of listening for signals, especially with the awesome ‘ears’ of Arecibo and the newer arrays such as the Very Large Array in New Mexico (where I am pictured from a visit in December, 2006).

“Absence of evidence is not evidence of absence.”
-- Carl Sagan

Let us be grateful to people who make us happy

2008-12-05T18:10:00.000-08:00

The title of this blog comes from French philosopher Marcel Proust who continued on to say of these cheerful friends that "they are the charming gardeners who make our souls blossom." For good companionship I'd pick Proust over his cynical countryman Camus, whom I quoted in my previous blog on happiness on 4/2/07 seen here along with the related one from the day before. My return to the contemplation of happiness was precipitated by my pleasure over recently released research showing that happiness is infectious. Evidently good news travels fast! :)

As reported by Karen Kaplan of the Los Angeles Times, scientists from Harvard and University of California at San Diego tapped into participants of the famous Framingham heart study to assess how happiness spreads. What I found most interesting was the one exception to the general rule that the best way to be happy is to surround yourself with happy people -- it does not work at work. Could that be true? I hope not. But I suppose that's why they call it "work" and not "fun."

PS. The photo of me comes from my recent work/vacation trip in Puerto Rico. The toothy statue is a pre-Columbian figure on display at the Historical Park of the Arecibo Lighthouse. My work was in Ponce for a medical device company that had the happiest employees that I've ever seen. I cannot describe the delight for a cold Minnesotan like me to be welcomed into such a warm environment as was nurtured by this Puerto Rican manufacturer. Perhaps this is the exception that proves the rule of no happiness spreading in the workplace. However, my intention is keep on smiling and being positive as much as I can wherever I am -- it makes me happier, that is for sure.

Roasty toasty in Puerto Rico

2008-11-20T15:48:00.000-08:00

I am enjoying a week of teaching class in pleasantly warm Puerto Rico (consider what it’s like in Minnesota this time of year!) and their servings of thick coffee with real cream and sugar. Normally I drink it black, but here I’ve been asking for el café con leche y con azúcar. One of my students, Jorge Nieves, gave me the heads up on some good PR coffee brands. He should know from growing up on a coffee plantation. Here are Jorge’s recommendations: Garrido Expresso, Alto Grande and Yauco select. The Yauco website says that the “University of Puerto Rico scientists studying the proximity of our farms to the Caribbean Sea theorize that micro nutrients are brought from the sea to the farm by the Alisian winds.” I cannot find anything on “Alisian” winds, but they feel good wafting in on my beachfront balcony!

Jorge explains that one must pay more for Puerto Rican coffee due to the relatively high cost to harvest the beans. The cherries (like the ones I pictured at a botanical garden outside Tampa) must be hand picked. November is the peak of production in Puerto Rico.

It seems to me that for this luxury of life the premium cost may actually add to its luster. However, Puerto Rican tourism officials may be overdosing on caffeine to think that their recent initiative for promoting coffee tourism will lure visitors inland from the lovely Caribbean beaches. On the other hand, how about a "surf and turf" vacation? That sounds good. After soaking up enough sun on the sand, then head for the hills and hit the haciendas. Now you're talking! (I really should call it quits for the day on drinking coffee.)

PS. Here are some interesting stats on coffee that I read in my airline magazine* while en route to San Juan from Minneapolis:
-- Coffee is known as “Joe” due to the US Secretary of Navy who in 1914 banned wine from officer’s mess – leaving only this hot, stimulating drink as an option.
-- It’s estimated that 1.6 billion cups of coffee are drunk worldwide every day. However, because the volume of a “cup” varies, no one can say how much coffee this really is!
-- The name Coffee is derived from “Kaffa” – a region in Ethiopia where in AD 800 a goatherd noticed his flock frolicking more than usual after eating certain berries. Fill in your joke here.
-- From Ethiopia “Kaffa” became the drink of choice for Arabians and then Europeans. A Dutchman established a plantation in Java in 1696 – hence that became a nickname for this stimulating drink.
-- Brazil is the leading country for coffee production -- 36 million 60 kg bags per year.
-- The manufacturer of Barcalounger claims they introduced coffee to the American workplace about a century ago in Buffalo. Didn’t they also invent spicy chicken wings?
-- Coffee seems destined to continually rise in popularity for the USA as evidenced by an increase in consumption by 18 to 24 year olds from 2.5 cups in 2005 to 3.1 in 2007 and 3.2 for 2008. ** (Americans measure a cup as 8 ounces – that’s nothing!)
-- The average American consumes 300 milligrams of caffeine per day.
-- Does drinking coffee help you stay awake behind the wheel? A French study measured the number of times coffee-drinking drivers crossed the center line. Those who took it decaffeinated crossed the line 159 times versus only 29 by the ones who kept the jolt in their Joe. Viva la difference!

*Source: “The Power of Joe” by Nancy Oakley, Delta’s Sky magazine, November 2008 .

** To counteract this assertion, I offer this anecdotal evidence: In the population of my 5 offspring and 2 in-laws – all younger than 30 years old – only one drinks coffee. The others go for caffeinated soft drinks (300 mg at least every day, I am sure!).

Where to draw the line on old wine

2008-11-14T19:48:00.000-08:00

Several years ago I gave a talk on design of experiments at a national conference of microbiologists in California. One of the other speakers in my session was an enologist (a scientist that deals with wine and wine making) from UC Davis – Associate Professor David Block. He helped me settle a debate in my family on how long one should keep wine stored after opening. Opinions ranged from indefinitely (years!) to less than 3 days as a guideline. My guess was 10 days at the max.

Naturally I thought of ways to put this to the test. My idea was to try a triangle tasting over time. Each taster is given three wines, two of which are the same. I saw this in a book I am read called The Drunkard's Walk, How Randomness Rules Our Lives. (By the way, the author thinks professional wine ratings are nonsensical for the most part -- purely random.)

However, after hearing from Prof Block, who like me is a U of Minnesota chemical engineer, I may not bother to experiment on aging wine because his answer fits my preconceptions (warning: technical details ahead!):

“The aging of wine is mainly related to the amount of oxygen in the bottle after it is opened, the amount of SO2 used by the winemaker for that particular wine, the wine pH, the amount of phenolics (more in red than white wines), and the amount of previous oxidation. So, for instance, if you only drink a small amount and put the bottle in the refrigerator, you are likely to see less oxidation than if you drink almost the entire bottle and leave lots of head space in the refrigerator.

My experience is that with sweet, dessert wines, I can leave them for months and they are still OK. This may be due to the winemaker adding more SO2 to decrease the chances of growth on the residual sugar. The SO2 can protect the wine somewhat from oxidation and production of aldehydes (typically associated with off-flavors or aromas).

Something like a sherry can be kept for a very long period of time at room temperature, typically because it is already oxidized during long barrel storage necessary to get the sherry-like characteristics (e.g. butterscotch, carmel, dried fruit aromas).

The effects of phenolics are a little more difficult to describe as they can be oxidized themselves, liberate H2O2 in reaction when they react with O2 (that eventually produces aldehydes), etc. However, it is generally felt that red wines with higher phenolics will last longer than white wines with lower phenolics. And...of course, all of these reactions are sensitive to pH and temperature.

That's kind of a complicated answer to your straightforward question...but it is a pretty complicated system. I keep off-dry white wines in the refrigerator for months. Dry reds and whites...probably less than a week. Sherries and ports and brandies...more or less indefinitely at room temperature.

Remember, that different people have different abilities to taste and smell various aromas and flavors, so one person's acceptable period may be different than a second person's period.”

So for the dry red wines I enjoy (tonight it is a boutique Syrah from Paso Robles California), I drink up the bottle within one week. That's my theory (with support from Prof Block) and I am sticking to it!

PS. Wine is fine for sipping and entertaining at the fancier soirees, but for an old-fashioned backyard barbecue it’s hard to beat a can of cold beer. The trick is keeping your brew cool on a steamy summer evening. Check out the results of this very enterprising and creative beer drinker who experimented on can cozies . The one made of rice krispies is unusual but I’d bet on a Thermos brand can insulator like this one that claims to keep your beverage cold ten times longer and 3 times longer than foam cozies.

Presidential polls perplexing

2008-11-06T10:59:00.000-08:00

Last week I heard interviews of top pollsters by a public radio host who could not accept that their results could vary so much – from a margin of 14 percent for Obama to only a 1 percent edge over his opponent McCain. Clearly these predictions differed significantly. Given the power of statistics, how could that be?

The main reason from what I gathered was the variation in pollster’s models on who will actually vote. For example, as I reported in my blog of 12/31/05 (“Surveys produce precisely inaccurate findings”), about 60 percent of self-stated voters did not cast their ballot in the previous election. This attrition rate historically varies by party (Democrats tending to slack off more than Republicans, perhaps) and demographics. Furthermore, people are more and more resistant to being polled – two out of three now refuse according to an article by Rick Montgomery of McClatchy Newspapers (11/2/08). Furthermore, the demise of landline phones in favor of mobiles makes it ever harder to even contact prospective voters. Who wants to burn up precious cell time on a poll?

Amazingly enough, despite all these difficulties in coming up with accurate predictions based on pre-election surveys, the political snapshots proved sharp according to Ken Dilanian of USA Today (11/6/08). Despite dire warnings by analysts such as political scientist Steven Schier of Carlton College (Northfield, Minnesota), I suppose that since all of the polls correctly forecast a win by Obama (his margin was 6 percent – in the middle of the pre-election range of predictions), the statisticians will get by with the usual excuse of “random variation – the old bell curve,” as Scott Rasmussen of Rasmussen Reports put it. Hopefully they learned some things that will lead to better models next time on who will actually vote, how unreachable cell phone users vary from readily-accessible ‘land-liners,’ and the behavior of the silent majority who refuse to answer any questions. Good luck and please take me off your call list.

PS. One of the more interesting statistics I heard about voting is that for every 1 inch of rain in any voting precinct the Republicans gain a 2.5 percent edge! Maybe McCain’s supporters should have invested in fire trucks to hose down voters waiting in line to vote.