All Features
Fred Schenkelberg
What if all failures occurred truly randomly? Well, for one thing the math would be easier.
The exponential distribution would be the only time to failure distribution—we wouldn’t need Weibull or other complex multi-parameter models. Knowing the failure rate for an hour would be all we would need…
Greg Fox
People say that I overthink everything. I’ve given this assertion considerable thought, and I don’t believe that it’s true. After all, how can any one person possibly overthink every possible thing in just one lifetime?
For example, suppose I live 85 years. That’s 2,680,560,000 seconds (85 years…
Beth Savage
The 2016 Masters Tournament is in the history books. Jordan Spieth had what some are calling an epic meltdown on the final nine holes of the tournament, and in a come-from-behind victory, Danny Willett earned the green jacket. The tournament is touted as a tradition unlike any other. Edge-of-your…
Bruno Scibilia
In yesterday’s column, I discussed how a DOE was chosen to optimize a chemical-mechanical polishing process in the microelectronics industry. This important process improved the plant’s final manufacturing yields. We selected an experimental design that let us study the effects of six process…
Patrick Runkel
About a year ago, a reader asked if I could try to explain degrees of freedom in statistics. Since then, I’ve been circling around that request very cautiously, like it’s some kind of wild beast that I’m not sure I can safely wrestle to the ground.
Degrees of freedom aren’t easy to explain. They…
Bruno Scibilia
Sponsored Content
Suppose that on your way to a summer holiday resort (a very distant place), your car breaks down. You might just call roadside assistance and wait for your car to be towed to a repair shop. But suppose that you think you’re smarter than that, and you would like to solve the issue…
Davis Balestracci
In part one yesterday, we looked at stats of the Boston Red Sox bullpen, a typical example of baseball’s tendency to find special cause in just about anything. The Boston Globe article on which these two columns are based has been a gold mine for teaching many useful, basic concepts about…
Davis Balestracci
In honor of baseball season, I’m going to apply some simple statistical thinking to my favorite sport in a two-part series today and tomorrow. I want anyone to be able to enjoy this, so I’ll mark any technical statistics as optional reading. For those of you interested only in the interpretations…
Jim Frost
P -values have been around for nearly a century, and they’ve been the subject of criticism since their origin. In recent years, the debate over p-values has risen to a fever pitch. In particular, there are serious fears that p-values are misused to such an extent that it has actually damaged…
William A. Levinson
Experiments that might require a handful of real-number measurements (variables data) could need hundreds or more attribute data for comparable power, i.e., the ability to determine whether an experiment improves performance over that of a control. Sample sizes needed for ANSI/ASQ Z1.4 (for…
Donald J. Wheeler
Context involves both the background for the data and how the data behave. This behavior of the data is most easily seen by using two complementary graphs—the running record and the histogram. Here I address the secrets of creating useful histograms.
The first graph mentioned above—the running…
Gilles Hilary
Phil used to be a very senior financial executive. When asked for a number, he would typically provide with a rough ballpark answer, such as, “It’s about 5 percent.” He’d then be peppered with questions about how he had arrived at that figure.
After a while, he got tired of this questioning and…
Davis Balestracci
April Fool’s Day (today) and the opening of baseball season (this Sunday) are upon us. To mark the first event, I’ll let my distinguished colleague Donald Wheeler make some eloquent and crucial statistical points that turn out to be, well, laughably simple. (No fooling!) Regarding the baseball…
Mike Micklewright
When considering any effort toward performance improvement, you should always start by looking at the organization’s principles and culture, and making sure these are aligned so they not only permit positive changes to occur, but also ensure that the changes will be sustained over the long run. By…
Patrick Runkel
I live with a German national, who often tells me that we Americans spend way too much of our lives at work. He also frequently comments that we work much less efficiently than Germans do, during the increased time we’re at work.
Which reminds me—I need to pay my water bill online....
OK, I’m…
John Elliott
Fly-fishing, one of my favorite hobbies, is a lot like process improvement. Here’s how: Fly-fishing seems very simple—you throw a line in the water and wait for dinner. Of course, it’s much more complicated than that because rainbow trout are clever; they won’t bite just anything.
You have to…
Eston Martz
There’s plenty of noisy disagreement about the state of healthcare, but when you look beyond the controversies, a great deal of common ground exists.
Many agree that the way we’ve been doing things is wasteful and inefficient, when healthcare should be delivered as efficiently and effectively as…
John Flaig
Sometimes when authors try to make a technical concept more understandable, it’s simplified but unfortunately, less accurate.
For example, when the developers of Six Sigma wanted to explain control charts and process capability analysis, they needed to include how the signal can be separated from…
Inderjit Arora
Objective auditing has always been a challenge, and this is especially true now for ISO 9001:2015 audits. To better meet customer expectations, fundamental changes have been introduced to the standard to address current business realities and advancements in technology. Much of the responsibility…
Greg Fox
Mind the gap. It’s is an important concept to bear in mind when traveling on the Tube in London, the T in Boston, the Metro in Washington, D.C., and other subways. But how many of us remember to mind the gap when we create an interval plot in Minitab Statistical Software? Not too many of us, I’d…
NIST
NIST scientists have devised and improved a prototype instrument the size of a loaf of bread that can substantially increase the accuracy of length measurements in commerce. Perhaps surprisingly, it does so by achieving the most accurate measure of the refractive index of air reported to date.
An…
Donald J. Wheeler
Here we look at a simple example to discover the commonalties of various data analysis techniques widely used in industry today. Careful consideration of the following may result in insights that were not part of your introductory class in statistics.
Our example uses the gate oxide thicknesses…
Diane Lee
Like many of you, I venture out on Saturday mornings to get groceries and gas. Until my college years, I never thought much about whether or not I paid the right amount at the pump, if the supermarket scale was correct, or if packaged foods actually contained the amount of product stated on the…
Joel Smith
For the majority of my career with Minitab, I’ve had the opportunity to speak somewhat regularly at conferences and other events. I thought some of my talks were pretty good, and some were not so good (based on ratings, audiences didn't always agree with my opinion at either extreme—but that's a…
Eston Martz
If you want to convince someone that at least a basic understanding of statistics is an essential life skill, bring up the case of Lucia de Berk. Hers is a story that’s too awful to be true—except that it’s completely true.
A flawed analysis irrevocably altered de Berk’s life and kept her behind…
