Where the radix point becomes a comma
Posted by mark in Basic stats & math on April 23, 2012
Prompted by an ever-growing flow of statistical questions from overseas, Stat-Ease Consultant Wayne Adams, recently circulated this Wikipedia link that provides a breakdown on countries using a decimal point versus a comma for the radix point—the separator of the integer part from the fractional side of a number.
For more background on decimal styles over time and place see this Science Editor article by Amelia Williamson. It credits Scottish mathematician John Napier* for being the first to use a period. However, it seems that he wavered later by using a comma, thus setting the stage for this being an alternative. Given the use of commas to separate thousands from millions and millions from billions and so on, numbers can be misinterpreted by several orders of magnitude very easily if you do not keep a sharp eye on the source.
So, all you math & stats boffins—watch it!
*As detailed in this 2009 blog I first learned of this fellow from seeing his bones on display at IBM’s Watson Research Center in New York.
Marshmallows measure the speed of light (and get put to other good uses)
One of my favorite blogs, Flowing Data, provided me the heads-up on a great lecture by Adam Savage (the Mythbuster’s guy) called “Simple ideas lead to scientific discoveries”. I really enjoyed all of his stories, but especially the one on Hippolyte Fizeau’s measurement of the speed of light in 1849. Ingenious!
Coincidentally, my brother Paul forwarded me a detailing of how one can measure the speed of light with a tray of mini-marshmallows! Check it out at this Science Blog written by theoretical astrophysicist Ethan Siegel. This sharp-fingered fellow (if you view his blog you will see what I mean) goes on to tout a marshmallow-made diorama that ‘peeps’ recent claims of particles going faster than the speed of light.
That leads me to puffing up my daughter Emily, who achieved the “peeple’s choice” award in the Saint Paul Pioneer Press Ninth Annual Marshmallow Peeps Diorama Contest. She and two of her closest peeps produced The Mupeeps Take Minnepeepolis. It looks very much like the view out of my window from Stat-Ease headquarters east of downtown Minneapolis.
By the way, my favorite Muppets are Bunsen and Beaker. See them demo their invention of fireproof paper here. At the Muppets Lab one should always be prepared with fresh marshmallows on a stick. I advise going for two at a time. o——<8
High rollers beat the lottery odds
Posted by mark in Consumer behavior on April 2, 2012
The $640 million jackpot in the Mega Millions lottery Friday night created a huge buzz. Unfortunately this fizzled out for all but the three big winners in Illinois, Kansas, and Maryland. Even we analytical types get swept up in the frenzy, seeing as how the money sunk in prior drawings brings the expected value over 100 percent. Yes, the odds of 1 in 176,000,000 remain daunting, but it sure is fun to have a few numbers to play with.
The really gutsy lottery wonks focus on other games where situations arise that make huge bets nearly a sure thing. For example, see this Boston Globe heads-up on “a game with a windfall for a knowing few”. Imagine showing up at your corner gas station with $100,000s in cash for lottery tickets—that would be a great day for the own, especially given the seller earns a commission that can grow to $100,000 for some jackpots.
“Bettors like the Selbees, who spent at least $500,000 on the game, had almost no risk of losing money.”
– Mark Kon, a professor of math and statistics at Boston University
Holing up on a frozen Minnesota lake
The March issue of Minnesota Business magazine, a valuable source of information and insight for growing companies,* provided a fascinating statistic, hard to believe really: 25,000—the number of ice fishing holes drilled last month for an ice-fishing contest on Gull Lake. Minnesota-based StikeMaster Corporation provided the augers. See their video for a demonstration.
Meanwhile (reported on page 44), elsewhere on Gull Lake (far from the 25,000 holes, I hope), Grand View Lodge offered the ideal meeting place for getting away from the office. See this report from our local CBS television affiliate—you will be amazed.
Sadly it seems that spring is nearly sprung so we must now endure 6 months of warm weather before the fun can begin again.
*Full disclosure: My daughter Emily is Graphic Designer for the production of this publication by Tiger Oak Media of Minneapolis.
Beware of obvious answers and positive results
Posted by mark in science, Uncategorized on March 4, 2012
“Most results, including those that appear in top-flight peer-reviewed journals, can’t be reproduced.”
This is a “dirty secret” revealed by the Wall Street Journal’s Gautam Naik in this December report. It cites statistics from Bayer that nearly two-thirds of published studies could not be replicated. Naik blames the complicated nature of experiments nowadays along with the “positive bias” researchers driven to produce results. Glenn Begley, vice president of research at Amgen, a biotechnology company, suggests that “academic scientists, like drug companies, should perform more experiments in a ‘blinded” manner to reduce any bias toward positive findings.”
Meanwhile, Duncan Watts, author of Everything is Obvious: *Once You Know the Answer says
“When you do the experiment properly [randomized and controlled], all the numbers go down.”
He’s speaking on the bias of marketing executives toward their own sensibilities, which often do not reflect those of the population being sold to. See what the Financial Times “undercover economist” Tim Harford says about this here. Unfortunately, in my experience, those (the analysts) who know better than to extrapolate from small, non-representative sample of opinions from the ‘powers-that-be’ (often n=1, that is—the Boss) get very little support for spending money to put these assertions to the test. Even though you know the top dogs might be barking up the wrong tree it’s easiest just to go along with the pack and press ahead. To do otherwise risks suffering a painful bite-back. Yes, I am a cynic.
Getting a head of beer
With winter winding down my thoughts turn to warmer times ahead when the cover comes off the grill and a cold beer hits the spot. Last weekend my daughter and her husband motored down to New Ulm for Schell Brewery’s Bock Fest—a sure harbinger of Spring (and the desperation of home-bound Minnesotans). Increasingly I find myself turning to this next generation for keeping me on the bubble for brews. For example, I now know that it’s helpful to carmelize freshly-tapped bock beer by poking it with a red-hot iron—preferably one laid among fiery logs until glowing hot. 
But never mind that, I want to pass along some results from another of this younger set, Tracy Lenz, on a more mundane aspect of drinking beer—achieving just the right head of foam on the pour. For a graduate class in industrial engineering at Arizona State University (ASU) taught by DOE-guru Doug Montgomery, she used Design-Expert® software to experiment on foam height. A local microbrewer suggested that Tracy’s project team study keg pressure, temperature at keg and using Biofoam to make the brew more ‘sudsy’. The team included two very different beers in the same experiment design, which turned out to be problematic for modeling, so let’s concentrate on one—an American red ale.*
It turns out that red ales foam readily so they need no encouragement with Biofoam. Take a look at this response surface plot from the ASU study. Figuring on 2 centimeters of foam as a good head puts the sweet spot (shaded green) at the no biofoam (-1) side with pressure needed to be set low (-1). This result is achieved only if temperature is maintained at low level.
So there you go—a vital problem (especially for graduate-engineering students) solved. Just one catch though—how you pour the beer into the glass may be the biggest factor for achieving a good head. Here again the next generation comes to my rescue, for example last summer at an outdoor reception that featured a beer wagon with my favorite on tap: Lift Bridge Beer Company’s Farm Girl Saison ale. My glass foamed over no matter how I positioned it under the tap. It turns out that the trick is pouring along the side and then at just the right moment straightening up the glass while turning off the flow. See what I mean via this Youtube video. I found it easier just to stand by the beer wagon with an empty pint and a forlorn look until one of the younger fellows took pity on me. Cheers!
*I learned from one of my sons that an ale ferments at the top, whereas a lager ferments at that bottom. This is just one of many differences that are detailed by this beer-faq.
Obscurity does not equal profundity
Posted by mark in Basic stats & math, sports on February 12, 2012
“GOOD with numbers? Fascinated by data? The sound you hear is opportunity knocking.” This is how Steve Lohr of the New York Times leads off his article in today’s Sunday paper on The Age of Big Data. Certainly the abundance of data has created a big demand for people who can crunch numbers. However, I am not sure the end result will be nearly as profitable as employers may hope.
“Many bits of straw look like needles.”
– Trevor Hastie, Professor of Statistics, Stanford University, co-author of The Elements of Statistical Learning (2nd edition).
I take issue with extremely tortuous paths to complicated models based on happenstance data. This can be every bit as bad as oversimplifications such as relying on linear trend lines (re Why you should be very leery of forecasts). As I once heard DOE guru George Box say (in regard to overly complex Taguchi methodologies): Obscurity does not equal profundity.
For example, Lohr touts the replacement of earned run average (ERA) with the “Siera”—Skill-Interactive Earned Run Average. Get all the deadly details here from the inventors of this new pitching performance metric. In my opinion, baseball itself is already complicated enough (try explaining it to someone who only follows soccer) without going to such statistical extremes for assessing players.
The movie “Moneyball” being up for Academy Awards is stoking the fever for “big data.” I am afraid that in the end the call may be for “money back” after all is said and done.
A debatable question: Should healthy people take cholesterol drugs?
Posted by mark in Uncategorized, Wellness on January 23, 2012
At my annual physical before my heart attack in December of 2004 I was advised that, although the cholesterol came in a bit high, it would not be necessary to go on medicine to reduce this. Would I have been spared if I had? This sort of speculation really does nothing for me but it underscores a big question that is debated in today’s Wall Street Journal: Should Healthy People Take Cholesterol Drugs to Prevent Heart Disease.
You be the judge whether the answer is yes or no—it is far too problematic for me to say. However, here are two points I want to make on the WSJ debate:
“we need clinical trials that actually follow healthy people treated with statins for the long term to see if treatment really results in lower mortality.”
I remain very skeptical of “experiments” comprised in a metamorphic manner by happenstance, as opposed to being truly controlled from start to finish and done double-blind (if possible).
Good bees and bad bees
People in my home state believe in a high degree of politeness which we deem Minnesota Nice. Thus it should be no surprise that entomologist Marla Spivak, who runs the Bee Lab at the University, has developed a trait for bees that she calls Minnesota Hygienic. These bees have been bred to detect and remove damaging diseases and parasites from the hive, thus lessening the likelihood of colony collapses that have confounded keepers nationwide. Spivak’s work came to my attention in this recent Washington Post article featuring beekeepers in nearby Maryland who get $165 for queens whose offspring do not tolerate parasitic mites and, hopefully, this zombie fly.
This concern over keeping bees healthy is not shared by everyone. For example, see this horrifying report from Florida (where I happen to be at the moment). If you fear bees (apiphobia), do not watch the video.
Favorite posts from three rings in the 2011 Management Improvement Blog Carnival (3 of 3)
Posted by hank in leadership on January 9, 2012
For the final blog review of the 2011 Management Improvement Blog Carnival I have chosen to review NOOP.NL, a blog about Agile software development and management by Dutch author (among other things) Jurgen Appelo. Being a software developer myself, this blog caught my eye. For those unfamiliar with Agile development, it is a method of software development that focuses on small, short iterations (called Sprints).
The first post that I want to share is actually not about Agile specifically – The Feedback Door is a clever method of getting feedback after a presentation or course. You put sticky notes on or near the door and ask people to stick their feedback directly on the door. Since the attendees need to pass through the door to leave, it’s difficult to ignore! Jorgen combines the feedback door idea with a “Happiness Index” (expanded on in this post) as a simple way to get quantitative feedback as well. It’s called, naturally, the Happiness Door.
Many of the posts in the blog are of a more philosophical bent (such as The Purpose of a Business is NOT Customer Value, and It takes Complexity to Handle Complexity). However, 21 Concrete Practices for Agile Managers stands out as a great collection of practical suggestions for Agile practitioners.
Finally, I liked this short and to the point post about the necessity of measures. It’s true that you can’t improve something without measuring some aspect of it. However as a commenter pointed out, you have to be careful what you measure. If you emphasize the wrong metric as a manager you may be encouraging the wrong behavior. A classic example in software is using lines of code (LOC) as a metric. This rewards sloppy and verbose coding and penalizes concise and elegant solutions to problems.