All Features
Greg Fox
Remember the classic science fiction film The Matrix? The dark sunglasses, the leather, computer monitors constantly raining streams of integers (inexplicably in base 10 rather than binary or hexadecimal)? And that mind-blowing plot twist when Neo takes the red pill from Morpheus’ outstretched…
Patrick Runkel
What does the eyesight of a homeless person have in common with complications from dental anesthesia? Or with reducing side-effects from cancer? Or monitoring artificial hip implants?
These are all subjects of recently published studies that use statistical analyses in Minitab to improve…
Davis Balestracci
In my last column I explained how many situations have an inherent response surface, which is the “truth.” However, any experimental result represents this true response, which is unfortunately obscured by the process’s common-cause variation. Regardless of whether you are at a low state of…
Donald J. Wheeler
The simple process behavior chart can be used in many different ways. Since report card data are common in all types of businesses, the report card chart is often the first chart that people create. Some of the pros and cons of report card charts are covered here.
Report card data are data that…
Patrick Runkel
The Pareto chart is a graphic representation of the 80/20 rule, also known as the Pareto principle. If you’re a quality improvement specialist, you know that the chart is named after the early 20th-century economist Vilfredo Pareto, who discovered that roughly 20 percent of the population in Italy…
Davis Balestracci
I’ve mentioned that design of experiments (DOE) is one of the few things worth salvaging from typical statistical training, and I thought I’d talk a bit more about DOE in the next couple of columns. The needed discipline for a good design is similar when using rapid-cycle plan-do-study-act (PDSA…
Brooke Pierce
The healthcare industry is in a state of constant change, and with change comes opportunity. With the passage of the Affordable Care Act (ACA) and the Medicare Access and CHIP Reauthorization Act (MACRA), healthcare providers are, or will be, paid differently for their services. No longer can they…
Donald J. Wheeler
Experimental designs that result in orthogonal data structures allow us to get the most out of both our analysis and our research budget. As a result, designed experiments have been used for everything from basic research to process optimization. These multiple roles make it crucial to understand…
Donald S. Holmes, A. Erhan Mergen
Regression analysis is used in a variety of manufacturing applications. An example of such an application would be to learn the effect of process variables on output quality variables. This allows the process control people to monitor those key variables and keep the output variables at the…
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…