Archive for category pop
“naked statistics” not very revealing
Posted by mark in Basic stats & math, pop on July 18, 2013
One of my daughters gave me a very readable book by economist Charles Wheelan titled “naked statistics, Stripping the Dread from the Data”. She knew this would be too simple for me, but figured I might pick up some ways to explain statistics better, which I really appreciate. However, although I very much liked the way Wheelan keeps things simple and makes it fun, his book never did deliver any nuggets that could be mined for my teachings. Nevertheless, I do recommend “naked statistics” for anyone who is challenged by this subject. It helps that author is not a statistician. ; )
By the way, there is very little said in this book about experiment design. Wheelan mentions in his chapter on “Program Evaluation” the idea of a ‘natural experiment’, that is, a situation where “random circumstances somehow create something approximating a randomized, controlled experiment.” So far as I am concerned “natural” data (happenstance) and results from an experiment cannot be mixed, thus natural experiment is an oxymoron, but I get the point of exploiting an unusually clean contrast ripe for the picking. I only advise continued skepticism on any results that come from uncontrolled variables.*
*Wheelan cites this study in which the author, economist Adriana Lleras-Muney, made use of a ‘quasi-natural experiment’ (her term) to conclude that “life expectancy of those adults who reached age thirty-five was extended by an extra one and a half years just by their attending one additional year of school” (quote from Whelan). Really!?
Kids & Science
Posted by mark in pop, science, Uncategorized on June 23, 2013
I am heartened to hear of great work being done by current and former colleagues to get K-12 kids involved in Science, Technology, Engineering, and Mathematics (STEM). For example, Columbia Academy, a middle school (grades 6-8) in Columbia Heights (just north of Minneapolis), held an Engineering and Science Fair last month where two of our consultants, Pat Whitcomb and Brooks Henderson, joined a score of other professional engineers who reviewed student projects. Winners will present their projects this summer at the University of Minnesota’s STEM Colloquium.
Also, I ran across a fellow I worked with at General Mills years ago who volunteers his time to teach middle-schoolers around the Twin Cities an appreciation for chemistry. He makes use of the American Chemical Society (ACS) “Kids & Chemistry” program, which offers complete instructions and worksheets for many great experiments at middle-school level. Follow this link to discover:
– Chemistry’s Rainbow: “Interpret color changes like a scientist as you create acid and base solutions, neutralize them, and observe a colorful chemical reaction.”
– Jiggle Gels: “Measure with purpose and cause exciting physical changes as you investigate the baby diaper polymer,* place a super-absorbing dinosaur toy in water, and make slime.”
– What’s New, CO2? “Combine chemicals and explore the invisible gas produced to discover how self-inflating balloons work.”
– Several other intriguing activities contributed by ACS members.
Kudos to all scientists, engineers, mathematician/statisticians who are engaging kids in STEM!
*(The super-slurpers invented by the diaper chemists really are quite amazing as I’ve learned from semi-quantitative measurements of weight before and after soakings by my grandson. Thank goodness! Check out this video by “Professor Bunsen”, which includes a trick to recover the liquids that I am not going to try.)
My man Mauer breaks a very curious baseball record
Listening to the Twins tonight and hearing my fellow high-school alumnus Joe Mauer strike out it occurred to me that he’s been doing this a lot lately. It turns out that Joe is whiffing at double his normal rate. However, this has had no effect on his performance other that saving him the trouble of legging out ground-ball outs. (I think that is Joe’s plan all along, that is, preserving energy.) Anyways, by racking up so many “K”s Mauer accomplished a 15-game hitting streak during which he struck out at least once in each game. According to Elias Sports Bureau, that breaks the previous record of 11 games for this oddly hot/cold hitting–at least since 1910, when the major leagues began keeping track of strikeouts.
That reminds me of a fellow I golfed with on Monday at a charity outing where we played best ball. He led off our four-some on the first tee with a mighty swing that raised a lot of dust but not the ball. Re-gathering his wits he swung even harder, but to no avail–the golf ball remained teed up. But the third time proved the charm–an awesome drive straight and far down the fairway that ended up being our best ball–none of the others of us could top it. So that works…albeit it is very nerve wracking for spectators, I must say.
Who foresees the future better—the Hedgehog or the Fox?
Posted by mark in pop, Uncategorized on June 5, 2013
“The fox knows many things, but the hedgehog knows one big thing.”
– Archilochus
In the June 3rd issue of Chemical & Engineering News Frederick M. Peterson, a chemical engineer who went on to achieve a doctorate in economics, dissects what happens when “Scientists Tackle Finance.” He warns against the tendency of experts in one field being overly bullish about their ability to manage things outside of their specialty. These are the hedgehogs—people who make bold predictions and happen to be right long enough that they attract a strong following.
On the other hand, the foxes, who observe many things and adapt readily to differing situations, lack confidence about the chances of any particular path leading to success. They are seen as being weak and wish-washy, which is not very popular. Nevertheless, it may not be surprising that foxes do better than hedgehogs at forecasting, according to Peterson, who cites a seminal study by the School of Business at University of California, Berkeley.
The moral of this story is to be wary of anyone who expresses too much certainty about the shape of things to come. It does not pay to follow hedgehogs—they will ultimately go beyond their narrow limits of competence and roll into something very prickly.
Brain disturbers make folks smarter or dumber (believe it or not)
Based on the underpowered experimental designs by neuroscientists reported in my previous blog, I am skeptical of these new findings, but they are very intriguing, nonetheless:
- Shocks to the Brain Improve Mathematical Abilities. (You ‘mathaletes’ should do some calculating before wiring up because the sample size for these findings is miniscule!)
- Brain, Interrupted-How distractions make us dumber. (The news here is mixed:Multitasking may be a myth but perhaps some people, with practice, can handle it.)
I hope this blog did not derail your train of thought. If so, go lick a battery to reverse the brain drain.
Educational system turned upside down by distance-based learning
Posted by mark in design of experiments, pop on April 14, 2013
I’ve been watching with interest the trend for ‘flipping’ classrooms; that is, using time together for working on homework and leaving the teaching to web-based and other materials (books, still!) for students to teach themselves on their own time. At the college level this new educational approach for is gaining momentum via massive open online courses, called MOOCS.
For example University of Minnesota chemistry professor Chris Cramer will teach this 9-week MOOC on Statistical Molecular Thermodynamics starting next month. Follow the link and watch him demonstrate a thermite reaction. If anyone can make statistical molecular thermodynamics interesting, it will be him, I think, so I enrolled. It’s free, thus there’s nothing to lose. Also, I still feel guilty about getting an A grade in the stat thermo class I took 30 years ago—the reason being it was graded on a curve and thus my abysmal final score of 15 out of 100 got rated highly as the second highest in my class. As you can infer, it was not taught very well!
P.S. I recently unveiled a distance-based lecture series on design of experiments called the DOE Launch Pad. It augments my book (co-authored by Pat Whitcomb) on DOE Simplified. Contact me at mark @ statease .com to sign up. It’s free for now while in pilot stage.
Statistics provide a decisive advantage to taking one route to work versus another
Posted by mark in pop, Uncategorized on April 7, 2013
See the results graphed on an experiment I just completed to decide whether to commute straight in to Minneapolis on Minnesota Highway 36 or take US Interstate 694 –a speedier, but longer, freeway bypass. Notice that the least significant difference bars do not overlap, thus providing more than 95 percent confidence that the scales tilt to one way (36) being faster–to put it simply.
For each run into work I randomly chose one route or the other based on a recipe sheet produced by Design-Expert software and timed it with a stopwatch app on my smart phone. Then I entered the results in the software and it gave me the answer I wanted.
It appears that I can save the better part of a minute by not shooting around on 694. That is good to know!
Statisticians break down March Madness brackets (and rule things in general)
Before the first round of NCAA basketball playoffs a number of pundits favored my Minnesota team to upset UCLA—one of the commentators before the broadcast last night went so far as to say they were a “lock”. Now I believe it. (They won.) However, I am doubtful they can beat Florida Sunday—gophers just do not stand a chance against gators. For a more reasoned breakdown on the odds for Sunday and beyond, see this bracket filled out superstar statistician Nate Silver for the New York Times.
People who can crunch data like Silver are in big demand these days according to Wall Street Journal Numbers Guy Carl Bialik in his column on March 2. The jobs site icrunchdata (very descriptive!) posted 28,305 openings for jobs in statistics and the like last month—up from 16,500 openings three years ago (I love data like this!).
It seems that number-herding nerds now rule, but there is a catch according to Dan Thorpe, senior director for analytics at Wal-Mart. He says that “the bulk of the people coming out [with statistics degrees] are technically competent but they’re missing the consultative and the soft skills, everything else they need to be successful.” So, which to do you prefer—good math skills (and lots of money) or an attractive personality (and many friends)? My advice is to aim for some of both.
Slugging down beer—which brew preferred by shell-less terrestrial gastropods
Inspired by my new web-based “Launch Pad” to the book DOE Simplified, PhD biologist Gaston Habets put his new statistical know-how to good use in his own backyard out in California by offering a choice of beer to the slugs eating up his garden.
Being a native of a cold clime I’d no idea how troublesome slugs could be until some years ago when my cousin in the Bay Area had me out to her place for dinner and asked me to help her gather up greens from the garden. The size of the slugs surprised me: The Pacific banana slug approaches a foot in length according to this New York Times science blog.
Given their gentle nature and top speed of 0.0055 miles per hour, one need not fear these slimy creatures. The only thing is that they eat up the gardens. So that sets the stage for the humane solution of sidetracking slugs with a bowl of beer. But which brew do they prefer? Gaston did his bit for the sake of garden science by setting out eight trays at specific locations around the vegetables and randomly pouring either Bud light or alcohol-free O’Doul’s. He repeated this experiment over four nights in a way that blocked out any differences in the nocturnal feedings.* The graphic shown here shows the outcome: By nearly a 3-to-1 ration slugs preferred Bud Light over the O’Doul’s. They did not get thrown off by the random location of the beer—the slugs found their favorite bars and bellied up.
*Gaston’s data showed a maximum slug count on Saturday night, but then they dropped off to a minimum on Sunday. My conclusion is that slugs party hearty. Who knew?
Slugs prefer Bud Light over O’Doul’s
P.S. It seems that slugs from coast to coast really do prefer Bud from what I see here.
Glass-shattering interaction of factors
Posted by mark in pop, Uncategorized on December 29, 2012
Last week (12/21) the Today Show broadcasted an alarming demonstration of Pyrex glass exploding after being subjected to certain combinations of conditions. See NBC News’ detailing here . As reported in this American Ceramic Society Bulletin , some scientists believe that changes to the material (replacing borosilicate with soda lime silicate) weakened the glass. However, makers of Pyrex disagree vehemently with these conclusions—see their side of the story here.
It turns out that hot Pyrex pans set directly on a wet or cool surface, such as a granite counter-top, undergo a sudden temperature change that produces some risk of it shattering. That strikes close to home for me, having re-done our kitchen (as is the style nowadays) with granite. Fortunately, being accustomed to plastic (Formica) countertops, I always put down cloth potholders before setting down the hot Pyrex pan. The take-home message is being careful not to subject Pyrex to rapid increases or decreases in temperature. See this site for safety instructions.
PS. On a lighter note (literally: too much sun) regarding heat and silica (main constituent of sand) see this New York Times news making it official that the hottest temperature ever recorded is 134 degrees F in Death Valley. They are pyre Rex.