Taking a shot at ruggedness testing with water pistols
Posted by mark in pop, Uncategorized on September 26, 2019
Being on the committee for ASTM International (formerly known as American Society for Testing and Materials) Standard Practice for Conducting Ruggedness Tests, I am a big fan of applying multifactor design of experiments (DOE) to systems before they go out to the field. For example, most homes in Florida feature stucco exteriors, which in some cases cannot withstand storm-driven rain from pushing moisture into the walls. Black mold can then build up to toxic levels before being discovered by home owners.
A less alarming, but still troublesome, combination of wind and rain is being combated by the trustees of Charles Rennie Mackintosh’s masterpiece Hill House in Glasgow, Scotland. The house, battered by rain every other day for 115 year, now soaks up water “like a sponge”. To keep it from dissolving “like a sugar cube”, National Trust Scotland (NTS) built a chainmail box around the home in June. They’ve scheduled a Douse the House this Saturday for visitors to test the ruggedness of the new exterior by shooting it with water pistols—”the bigger the better”! The experiment takes place at 2.30 pm and entry is free.
NTS’s Douse the House organizers had best beware of Mark Rober and his Guinness World Record sized Super Soaker. That might turn out to be a destructive testing device, even with chainmail as the barrier.
Stupid dad jokes work with a little help from prearranged laughs
“Why don’t you hear a pterodactyl go to the bathroom? …(dramatic pause)… “The P is silent!”
I had to laugh out loud at this dad joke reported by Scott Simon of NPR in this June 15 Weekend Edition.
I came up with a good one myself the other day while helping my daughter Carrie fill up tires on a new bike carrier that she bought for my grandson. To be sure of enough pressure, I “aired” on the high side. Explaining this to her, I held up my arms and fingered air-quotes when I said “aired”. Carrie gave me an eyebrow-raised, squinty-eyed, pursed lips look, from which I could tell that she was greatly amused.
Nothing will deter me from telling my awesome dad jokes. However, I wish they would elicit more guffaws than groans. Fortunately, neuroscientists at University College London (UCL) have come to my rescue with advice on how to generate LOLs from puns and other forms of high humor dispensed by dads like me. The trick is to play a sound track of genuine laughter just after telling the joke. (It turns out that Hollywood knew what they were doing by dubbing in laugh tracks.) As reported in “Modulation of humor ratings of bad jokes by other people’s laughter” (Current Biology, July 22, 2019), the UCL team provided empirical evidence that adding laughter indeed increases how funny a joke is perceived to be.
Despite all this attestation from Hollywood and neuroscientists, I remain skeptical of laughter being infectious. Although I always laugh loudly after every one of my dad jokes, I keep getting these weird looks a la Carrie. Or when I attempt to lighten things up with my wife, it generally elicits only the standard “very funny, Mark”. (She knows that this is the only way to get me to temporarily cease and desist on humor.) Although I enjoy laughing at my own jokes, it seems that I need an outside source of chuckles to keep the guffaws going.
Central Casting in Hollywood supplies professional laughers at $100 per hour, but that’s too pricey. For now, I might keep this canned laugh track handy on my smartphone hidden in my back pocket. If that doesn’t work, I can always dig out my flatulence-simulating whoopee-cushion. This never fails to get attention!
P.S. Little known fact: The first dad joke on record is “Cleopatra walks by and Julius sees her.” An alternative version is “Look! Cleopatra walks by. Julius, seize her!” Now, play the laugh track. These puns are hilarious!
Designed experiment creates egg-splosive results
Posted by mark in design of experiments, Uncategorized on August 20, 2019
Design-Expert® software version 12 (DX12) released this summer with a cool new tool to model binary responses, for example, pass-versus-fail quality-testing. For what it’s worth, the methodology is called “logistic regression”, but suffice it to say that it handles results restricted to only two values, typically 0 or 1. The user deems which level is a success, most often “1”.
During development of DX12 Stat-Ease moved to a penthouse office on a building with a cascade of balconies. So, when our programmers, led by Hank Anderson, considered how to test this feature with an experiment, they came up with the idea of trying various packing on eggs to see if they could be dropped some distance without breaking—a project that high-school science teachers assign their students. However, we figured that our neighboring tenants down below and our new landlord might not be very happy about the mess that this would create. Therefore, Hank and his team took a less problematic tack by testing various factors for microwaving eggs to an edible stage. This experiment (or ‘eggs-periment’ if you like) also was more productive for varying the diet of the programmers from their staple of boiled ramen noodles—the focus of a prior DOE.* If they could achieve consistent success in cooking eggs by microwave, a combination of these with ramen might be the ideal sustenance for awesome coding for new versions of Design-Expert.
The Stat-Ease experiment began with a bang during the range-finding stage with an explosive result. You might say that the yolk was on us—bits of overcooked egg and shell dispersed throughout the chamber of the microwave. The picture below shows the messy aftermath (note the safety glasses).
After this learning experience (‘eggs-perience’?), Hank and his lab technician, Mike Brownson, settled into a safer range of factors, shown below, that kept the contents from reaching the catastrophic breaking point:
- Preheat—0 to 180 seconds
- Cooking time—120 to 420 seconds
- Power—60 to 100 percent
- Salt—0 to 2 teaspoons
- Egg Size —Large or Jumbo
Hank and Mike, with input from Stat-Ease Consultant Martin Bezener, put together an ambitious design with 92 runs using Design-Expert’s custom design builder (i-optimal) for response surface methods. Heads-up: When responses are restricted to just two outcomes (binary), many more runs are required to provide adequate power than would be required for a continuous measure.
The investment of nearly 100 trials for the ‘eggs-periment’ paid off by producing significant results on pass/fail measures of undercooking and overcooking. For example, the 3D graph below shows the probability of eggs being undercooked as a function of time and power for the microwaving. Notice by the corner at the left being cut off that potentially catastrophic combinations of high power and long cooking were excluded via a multifactor constraint. Clever!
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Based on models produced from this experiment, Design-Expert’s multiple-response optimization recommends a most desirable setup for microwaving eggs as follows: Heavily salted jumbos preheated to the maximum level and then cooked for 315 seconds at medium power.
Thanks to the research by Hank, Mike and Martin, our programming staff now is fueled not just by ramen, but also with eggs—a spectacular success for DX12’s new logistic-regression tools!
* “The Optimal Recession-Proof Recipe”, Brooks Henderson, pp 1-2, September 2012 Stat-Teaser, followed up by “Confirming the Optimal Ramen”, p3, January 2013 Stat-Teaser.
Pop tops collected for charity and for the fun of counting
When my oldest grandchild Archer reached the age to walk rather than be pushed around the neighborhood in a stroller, he noticed lots of shiny tabs laying on the road. Knowing full well that these have no special scrap value than the can itself, I encouraged him to pick these up for the reduction in litter. This became a fun game for a few years. I’d keep some tabs in my pocket and surreptitiously toss them out for the joy of discovery, us having picked all the streets clean already.
When Archer outgrew the tab game, I continued to collect them for Ronald McDonald House Charities (RMHC)—them being happy to play along for the easy money from clean and closely-packed aluminum. Yesterday, after popping off tabs for 5 years or so, I emptied out my bottle (pictured) at the Minneapolis chapter.
Here are some interesting statistics on pop tabs that I gleaned from the internet:
- They were invented in 1974.
- There are 1,267 in one pound.
- The value of scrap aluminum ranges from 30 to 40 cents per pound.
- The Minneapolis RMHC started the Pop Tab Collection program in 1987, which then spread nationwide–they have raised more than $800,000 for their chapter alone since the founding.
Before turning in the tabs, I ran a contest with 24 of my relatives at our annual reunion last week. I started it off with my guess of 1500, which evidently biased the estimates because they came out to very near that value on average. Using the new histogram feature Design-Expert® software version 12, I produced the graphic shown. The program’s diagnostic tools revealed a nearly normal distribution other than one overly high guess from one of my brothers-in-law, who incorrectly extrapolated how many beverages I drink from observation of the quantities being consumed at the reunion.
The actual count was 1838. The winner guessed 1858 for first prize of ten dollars. Archer, now 8, helped me count, came in second and won two dollars plus another dollar for assisting. He was thrilled.
I’m starting up a new collection now. It’s a bother to bend them off the cans before I crush them but it’s a habit that provides a very small measure of satisfaction every time I drop one in the bucket.
“You touch the stupid object, you change the stupid object”
So, according to the Wall Street Journal*, says Jon Pratt, a mechanical engineer with the U.S. National Institute of Standards and Technology (NIST). He was speaking about a cylinder of platinum-iridium forged in 1889, known as “Le Grand K”, which on May 20 went out of service as the kilogram standard.
Metrologists worldwide now will define this weight by non-physical methods based on non-changing constants of the universe. It will be measured by a high-tech tool called the Kibble balance.
For a detailed explanation of the new kilogram standard and a fascinating video of NIST’s Kibble balance in action, see the Wired magazine post by physics professor Rhett Allain on The Basic Physics of the Kilogram’s Fancy New Definition. Weighty stuff! (A bit too dense for me—I just like the Kibble…mesmerizing.)
*(“The Numbers” by Jo Craven McGinty, “The Kilogram Faces a New Test of Metal”, 6/8/19)
Over half of all children have below-average reading skills
Posted by mark in Education, leadership, pop, Uncategorized on June 24, 2019
Yes, you read that right—this statistic was cited by Eugenia Cheng last weekend in her column for the Wall Street Journal on why Averages Aren’t Always What They Seem. In this case, a small number of excellent readers skews the distribution to the right.
But none of this applies to my offspring, them being in the Lake Wobegon region where all the children are above average.
I would never admit it, but deep down I realize that I’ve succumbed to the superiority illusion, aka the Dunning-Kruger effect. As advised in this June 3rd post by Forbes you’d best be careful not to be taken in by individuals who consistently overestimate their competence due to this cognitive bias.
Steve Carell took the superiority illusion to an absurd extreme as the manager Michael Scott in the “The Office” television series. It’s funny unless you are subject to someone like this.
“The knowledge and intelligence that are required to be good at a task are often the same qualities needed to recognize that one is not good at that task—and if one lacks such knowledge and intelligence, one remains ignorant that one is not good at that task.”
— David Dunning, professor of psychology at the University of Michigan
“Stupid people are so stupid they’re unable to grasp the fact that they’re stupid.”
— Letter to Editor of Oroville Mercury Register, 6/23/19
Park in the first open spot or chance one opening much closer?
Posted by mark in pop, Uncategorized on June 6, 2019
Up until a few years ago when going to an event with limited parking, I always took the first opening available. But then one of my buddies told me how he prays for a closer place and one always opens. I thought about that and came to an epiphany that, as a general rule, one may as well try for a parking spot as close as possible to the destination. That’s been working for me ever since.
This strategy is now validated by researchers who evaluated three alternatives: meek, optimistic and prudent. They mathematically disrespect the meek driver parks at the first available spot that is behind the most distant parked car.
“The meek strategy is the most stupid strategy.”
Professor Sidney Redner, Santa Fe Institute—co-author of Simple Parking Strategies, Apr 14, 2019
However, the optimistic driver (like my prayerful friend) who goes for the closest spot, bypassing any gaps before the destination, pays a big penalty if they fail–going all the to the back of the parking line and being late for their even. It is better to be prudent—the middle strategy—by parking at the first gap.
Being methodical and frequently searching for parking at sporting events, I am very appreciative of this analysis. It reinforces my new-found faith (thanks to my friend) that the meek do not inherit the earth, at least not a good place to park your car.
ASA calls for abandoning the declaration of results being “statistically significant”
Posted by mark in Basic stats & math, Uncategorized on May 1, 2019
On March 21 the American Statistical Association (ASA) sent out a shocking email to all members that the lead editorial in a special, open-access issue of The American Statistician calls for abandoning the use of “statistically significant”. With irony evidently intended by their italicization, they proclaimed it “a significant day in the history of the ASA and statistics.
I think the probability of experimenters ignoring ASA’s advice and continuing to say “statistically significant” approaches 100 percent. Out of the myriad of suggestions in the 43 articles of The American Statistician special issue the ones I like best come from statisticians Daniel J. Benjamin and James O. Berger. They propose that, because “p-values are often misinterpreted in ways that lead to overstating the evidence against the null hypothesis”, the threshold for “statistical significance” of novel discoveries require a threshold of 0.005. By their reckoning, a p-value between 0.05 and 0.005 should the be degraded to “suggestive,” rather than “significant.”*
It’s a shame that p-hackers, skewered in this xkcd cartoon, undermined the sound application of statistics for filtering out findings unsupported by the data.
*The American Statistician, 2019, Vol. 73, No. S1, 186–191: Statistical Inference in the 21st Century, “Three Recommendations for Improving the Use of p-Values”.
Money buys happiness unless you get caught up in the Easterlin paradox
Posted by mark in Uncategorized, Wellness on April 23, 2019
The March 23rd issue of The Economist provides an interesting graphic on GDP per person—a measure of wealth—versus self-reported happiness. Overall it shows an upward trend that increases life satisfaction by 0.7 points (on a 10-point scale) as GDP doubles.
China is a prime example of money buying more happiness. Sadly, us citizens of the USA (and many European countries) are subject to the Easterlin paradox, which puts a limit on how satisfied people get as their income rises, beyond which money cannot buy more happiness.
Check out this interactive online version of the happiness vs wealth posted by The Economist. There, if American, you will see with some satisfaction (misery liking company) that Netherlands and several other wealthy countries share our downward trend. However, Germany and Britain remain on the upswing. (I wonder with Britain now in the throes of Brexit if their GDP will shrink and, if so, suspect that their happiness will also fall off.)
So, bottom line, for those of us stuck in the paradox, would you rather be richer or happier? That is a tough question!
The Economist claims to master forecasts for major men’s golf tourneys
The Masters, the first of four major men’s golf tournaments this year, reaches its midway point today. Many fans are following Tiger Woods to see if he can complete his comeback by adding a 5th Green Jacket to his collection. A gambler in Nevada bet $85,000 on Tiger to win for a $1,190,000 payoff. Check out his current chances at this Economist Advantage in Likelihood Estimate (EAGLE) forecaster. Their algorithm likes Tiger’s chances more than his Official World Golf Rankings would indicate. If you enjoy golf as well as statistics, EAGLE will hit the spot. Check it out!