Patrick Runkel
It’s usually not a good idea to rely solely on a single statistic to draw conclusions about your process. Do that, and you could fall into the clutches of the “duck-rabbit” illusion shown below.
If...
Donald J. Wheeler
While the computations for a process behavior chart are completely general and very robust, the secret to using a process behavior chart effectively lies in the art of rational sampling and rational...
Dawn Keller
Generally speaking, I have a problem with authority. I don’t like being told what to do or how to do it. I’m not proud of that.
I recall debating with my high school trigonometry teacher regarding...
Donald J. Wheeler
Parts per million (ppm) is part of the language of Six Sigma. It pervades the sales pitch and is used in all sorts of computations as a measure of quality. Yet what are the rules of arithmetic and...
Donald J. Wheeler
The first axiom of data analysis is: “No data have meaning apart from their context.” Yet we all encounter measures that have been dreamed up without regard for either context or use. This column...
Patrick Runkel
Right now I’m enjoying my daily dose of morning joe. As the steam rises off the cup, the dark, rich liquid triggers a powerful enzyme cascade that jump-starts my brain and central nervous system,...
CorDEX Instruments
NFPA 70E, full title “NFPA 70E—“Standard for Electrical Safety in the Workplace,” is a standard written by the National Fire Protection Association (NFPA). NFPA 70E was created primarily to...
Dawn Keller
Juvenile idiopathic scoliosis. That was the diagnosis given to my then 8-year-old daughter last January. In short, it means that she’s young (under 10), she exhibits an abnormal amount of spinal...
Donald J. Wheeler
Author clarification--3/5/2015:It appears that I somewhat overstated my case in this article. I had forgotten that there are some families of distributions where we can estimate the shape of a...
Joel Smith
I typically attend a few lean Six Sigma conferences each year, and at each there’s at least one session about compensating belts. There are any number of ideas for how to do so, but they commonly...
Patrick Runkel
If you’re not a statistician, looking through statistical output can sometimes make you feel a like you’ve wandered into Alice in Wonderland. Suddenly, you find yourself in a fantastical world...
Donald J. Wheeler
Whenever the original data pile up against a barrier or a boundary value, the histogram tends to be skewed and non-normal in shape. Last month in part one we found that this doesn’t appreciably...
Dawn Keller
I really can’t make this stuff up.
I wrote a post a couple of years ago titled: “How to Talk to Your Kids About... Quality Improvement,” in which I lamented about Community Hero Day in my...
Joel Smith
On a recent vacation, I was unsuccessfully trying to reunite with my family outside a busy shopping mall and starting to get a little stressed. I was on a crowded sidewalk, in a busy city known for...
Greg Fox
At the end of part one, aspiring statisticians Woodrow “Woody” Stem and August “Russell” Leaf, creators of the famed Stem-and-Leaf plot, were in bad shape. They had beaten each other statsless...
Donald J. Wheeler
Whenever the original data pile up against a barrier or a boundary value, the histogram tends to be skewed and non-normal in shape. In 1967 Irving W. Burr computed the appropriate bias correction...
Greg Fox
Greetings, fair reader. In the past, I've written several articles with practical tips related to Minitab graphs, such as how to discuss the sensitive issue of p-charts and Laney P' charts...
John Flaig
Engineers have used safety margins for centuries to protect their companies and customers from the consequences of product degradation and failure. Sometimes the safety margins are fairly obvious (...
John Flaig
The claim is made and widely believed that C = 0 sampling plans are more cost effective than classic sampling plans such as ANSI/ASQ Z1.4. Below is a preliminary analysis of the cost difference...
Dawn Keller
I spend the majority of my time entrenched in statistics. Using statistics. Studying statistics. Developing and testing statistical software. Statistics guide many of my decisions at work and in...
