Tom Murphy and Peter Fortini recently published a great answer to the question of how many significant digits to use when reporting test results relative to manufacturing specifications.* All engineers (such as me) know not to round the intermediate results of a multistage calculation. Nevertheless, it’s good to be reminded of this. However, I was unaware that, when rounding a test result for reporting purposes, the interval should be between 0.05 and 0.5 sigma. Murphy and Fortini offer the example of a test result of 1.45729 with a standard deviation of 0.00052, which leads to a rounding of 1.457 (the nearest thousandth). That’s good to know!

I guess that I’ve been slacking off on this rounding deal because I was also ignorant of the “five-even” rule that these two authors note as being de rigueur for “most standards for science and technology.” For example, this rule causes 98.5 to be rounded down to 98, whereas 99.5 gets round up to 100.

My informal survey of math-literate acquaintances revealed that most had learned only to round 5 and higher up (and 4 and lower down). However, my son Hank, a programmer by profession, was familiar with the five even rule, which this Wikipedia entry on rounding says is also known as “statistician’s rounding.” That makes sense because when dealing with large sets of scientific data, where trends are important, traditional “five-up” biases the data upwards.

When I worked in R&D, I noticed that my fellow engineers seemed to be scared to death of rounding – even when reporting their results to non-technical management – marketing folks and the like. Reporting data to a dozen decimal places generally blunted their spear, whereas rounding their numbers to no more than three significant digits would have made their point a lot sharper. Isn’t that ironic?

* “Reporting Test Results, Determining Significant Digits and Rounding Properly,” ASTM Standardization News, September/October 2008 (link for article content may require subscription )

Yesterday, which happened to be Talk Like a Pirate Day, I did a pro bono webinar for a crew of food scientist students assembled by their teacher Tyre at North Carolina State University . They are located in Raleigh – not far from where the notorious Blackbeard hung out in his hay days. Evidently he hosted some very wild parties with his bloodthirsty cohorts, as detailed at this Pirates Realm . (Their webmaster warns that copyright “thieves shall be gullied and fed to the sharks!”)

Tyre and his NC State crew concocted a punch that purportedly imitated an orange drink similar to Kool Aid® — a brand of artificially-flavored drink mix now owned by the Kraft Foods Company but originally invented by Edwin and Kitty Perkins of Hastings, Nebraska.

Now I know that no Carolinian would touch such a tame Midwestern beverage. Thus I strongly suspect that NCSU keeps at least a firkin of rum handy for their apprentice galley slaves – oops, I meant to say food scientists. I am thinking that rum may be the principal component in the mysteriously unidentified “flavor” in the recipe sent to me by Tyre. Given that the a proper rum-laced pirate grog often included lime juice to help to stave off scurvy and a measure of cane sugar to help kill the bitterness of the water, it stands to reason that this NCSU “orange drink” also contains citric acid and sucrose. However, being as I was without a spyglass for this webinar, who knows what this piratical Carolinians were up to.

The treasure these tasters seek is 5 on a 0 to 10 intensity scale. Notice on the graph how they favor this so-called “flavor.” As a statistician turned pirate I say ahRrrrggg-Squared to that. They’d best send me a hogshead of this so-called “kool-aid” or I will be forced to send Tyre the Black Spot in lieu of my usual report.

Thank goodness for my son Hank (pictured) who knows the ropes of modern information technology (IT). At the suggestion of another IT whiz – my brother Paul – Hank added a new link below the quote on the StatsMadeEasy web page that allow you to Subscribe via Email. Then the latest StatsMadeEasy missive will magically appear in your electronic in-box and possibly provide a “bright spot in a dull day” (as one of my readers kindly complimented me).

For those of you that are more sophisticated on blogs, we offer a mechanism to provide a Site Feed. This is done via Feedburner – a provider purchased by Google for a very large sum – reportedly. If you’re one of the legions like me that are mired in a love-hate relationship with Microsoft and their personal information manager Outlook, you may need this help on how to Add an RSS Feed.

I keep tabs on two blogs — the Curious Cat Science and Engineering Blog by John Hunter and one by William M. Briggs, Statistician, which offers “All manner of statistical analyses cheerfully undertaken.” These go automatically into separate RSS Feeds folders that I browse when I need a bright spot to break up a dull day. (Caution: Briggs tackles some controversial subjects.)

What’s in for you to convince those funding your research that you are on the right track?

I once wrote a proceeding for a technical talk that featured active sentence structure with my familiar style of writing, in which I strive to write on a personal note (it’s all about “you”). The moderator, a PhD scientist, chastised me for not using passive language and keeping the tone impersonal (no “you” turns of phrasing allowed!). She told me that this was mandatory for a technical publication – in other words, dull my writing down to make it more boring and uninspiring.

“When it comes to writing engaging content, “you” is the most powerful word in the English language.”
— Brian Clark, The Two Most Important Words in Blogging

Similarly, I’ve seen many engineers suck the life out of exciting discoveries. They do this by starting from the most mundane details and then methodically building their case in a “scientific manner.” Such a train of thought derails all but the most tenacious and technically-savvy reader. Granted, this must be done for academic journals, but presentations that go over the top scientifically frequently fall flat in the high-flying world of industrial R&D.

I am reading a book of short stories by a writer who captured the spirit of living on the edge – Jack London. Although he is best known for stories of Alaskan adventure, such as “The Call of the Wild,” London also wrote of the rough-and-tumble world of the newspaper business in the early 1900’s – a time when William Randolph Hearst ruled the roost with his sensational journalism. I came across this good advice for aspiring writers by a character in Jack London’s short story “Amateur Night” (1903):

“Be terse in style, vigorous of phrase, apt, concretely apt, in similitude. Avoid platitudes and commonplaces. Exercise selection. Seize upon things salient, eliminate the rest. … Tell it all in the opening paragraph as advertisement of contents, and in the contents tell it all over again. Then put a snapper at the end.”

Does this not tell what you need to do to put some pizzazz in your presentations? Go for it!

I heard this fellow Colin A. Ross interviewed on radio last week. He patented a switch that, with a bit of training, can be activated by eye via a beam of energy. For example, let’s say you have your iPod set up to be an “eye” Ipod. Then you could just look at it to start up the music!

Here are some of the assertions I heard over the airwaves from Ross:
– eye beams explain how one feels a person staring at them
– via survival of the fittest, animals such as gazelles can sense when predators like lions focus on them
– military snipers learn not to look too intensely at their targets because they can get spooked
– eye beams are not energetic enough to cause any harm — they are not like lasers
– a person can lock on to an eye beam aimed at them — for example, while hunting for rabbits, Ross felt one staring at him and turned around to shoot it without having to search it out (he ate the rabbit for dinner that night).

Although this last assertion I heard from Ross goes a bit over the top, he sounds very scientific – a reflection of impressive credentials in psychiatry. So I asked my sister, an ophthalmologist who specializes in laser eye surgery, whether she considers Ross’s claim to be credible. Here’s her comments: “I have never heard of him, but I found this report describing his eyebeam of energy on the web. Eye beams are not beyond theoretic possibility but I have never ever heard of anything like this (one would think with the opthamology literature I routinely survey that I would have come across some mention of energy emissions). I think it more likely that Dr. Ross has exceptional hearing, quick reflexes, and good spatial sense which allowed him to shoot and subsequently eat the rabbit, for example. Light is definitely reflected from the eye (hence the red-eye camera effect). However, it seems hard to imagine that even this energy would amount to much after a short distance.”

Dr. Ross hopes to be tested by scientific skeptic and former magician James Randi to achieve his One Million Dollar Paranormal Challenge. For more details, see this press release put out by the Colin A. Ross Institute based in Richardson, Texas.

I am keeping my eyes open for definitive proof of eye-beams. Meanwhile I am trying to perfect a penetrating stare, while at the same time watching my back for apprentices of Ross who have mastered the ability to generate extramissions out of their eyeballs. However, I think that, after withstanding almost 34 years of looks from my rightly-irate wife, nothing short of a LaserCat can penetrate my battle-hardened skin.

My assistant Karen, knowing that I am fond of chemicals (being an engineer in this specialty), sent me the link to The University of Nottingham’s periodic table of videos. If you are a pyromaniac, check out their flick on phosphorus. I learned that an average person processes 70 kilos of phosphorous — an essential element for human life. That makes me wonder if the stories of people spontaneously combusting could be true!

I enjoyed the video on arsenic — an element I worked with on my first job after graduating in chemical engineering from the University of Minnesota. My supervisor handed me several bottles of varying forms of arsenic and suggested that I dope them into a quantity of shale oil. My mission was to experiment on adding various metals that might tie up the arsenic in the solid ash. This toxic element occurs naturally in shale oil, which, when burned, creates an oxide that sublimates on nearby greenery. For example, the rabbits eating outside the shale-oil power plant might go cotton-tail up after enjoying their salad. I had no idea how to construct a lab-scale combustion chamber so I simply poured some oil into a ceramic ‘canoe’, added a pinch of arsenic, put the canoe into a pyrex cylinder and heated it up with tube furnace. Sometimes the oil would vaporize and explode — shotting the stopper around the lab like a rubber bullet. Thus I took the precaution of standing in the hall, which made some colleagues wonder what I was doing all day.

My supervisor took a one month vacation while I completed this introductory project as a new engineer. He looked surprised to see me upon his return.

One thing I learned about arsenic from the video guy with the crazy hair — research professor Martyn Poliakoff of the University of Nottingham — was that in the Victorian age it was an essential element for the green dye used in wallpaper. Unfortunately, when water seeped into the walls, the mold converted the arsenic to a volatile form that killed a number of homeowners. I’d have thought the arsenic would have killed the mold, but I suppose that would be too convenient.

Out of the land of the blue-sky waters, my daughter Carrie called me collect last week from the Boundary Waters Canoe Area wilderness region in the far north of Minnesota. The group of Girls Scouts led by her and another counselor were forced back to the start of their trek by a bear who took all their food. Evidently this particular creature learned via trial and error experimentation that by pulling on the rope it collect a tasty cache of treats. In any case, it did not scare when Carrie yelled and brandished a rain pancho. When the bear advanced menacingly – growling with teeth bared, the Girl Scouts decided they really did not want their food!

Apparently mid-summer is not as bountiful for bears as the spring or fall (when berries abound). Carrie told me that the bear pulled so hard on the nylon rope that it melted the surface from the friction! A friend of mine who grew up in Duluth told me that a bear in their area got so good at collecting food from campers that it collected up dozens of packs that were eventually discovered in an astonishingly large discard pile out in the woods.

Perhaps this unbearably bad behavior could be extinguished by a dousing like that experienced by the monkeys noted in my blog of July 09, 2006. However, the bear in the picture would probably enjoy the option of a shower over a bath.