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Eston Martz

I’m not a “math” person, but I've overcome fear of statistics and acquired a real passion for it. And if I can learn to understand and apply statistics, so can you. Continue Reading »

Like a lot of people who need to analyze data for their work, I am not an expert statistician. Over the years I've acquired a fair amount of knowledge and experience, but mainly enough to make me appreciate more than ever the value of statistical software in making data analysis an accessible tool.   And I've discovered over and over again how quickly specific statistics skills can get rusty if you... Continue Reading
Did you ever have a column of numeric data you wanted to simplify?  For instance, numbers with 5 or 6 decimal places where only 1 is needed?  Here's a neat way to do it in Minitab Statistical Software, using the Calculator tool's FIXED function. This function rounds a number to the specified number of decimals and converts it to text, with or without commas.    As you can see in the dialog box... Continue Reading
Probability is the heart and soul of statistics: at a very simple level, we collect data about something we wish to understand, then we use statistics to assess the likelihood—or probability—of the situation described by the data. In practice, this simple idea gets complicated very quickly. Anyone who's been involved in a 6 Sigma project can confirm that sometimes the data we collect, and the... Continue Reading
Text data can be a challenge to analyze.  Even the word "data" usually makes me think about numbers, but a great deal of the data statisticians and quality professionals need to analyze is text.  Now, I majored in English as an undergraduate, so I find it very interesting to think about literature in terms of the data it contains. For instance, I'd love to treat Thomas Pynchon's The Crying of... Continue Reading
Choosing an appropriate Six Sigma project is challenging, and one of the biggest areas of risk involves the size and focus of the project. A simple form referred to as a SIPOC can be a big help when it comes to selecting a project that has a high likelihood of success. I explained in some detail what a SIPOC is in an earlier post, but here's the bottom-line version. The SIPOC acronym stands for Supp... Continue Reading
It's all too easy to make mistakes involving statistics. Powerful statistical software can remove a lot of the difficulty surrounding statistical calculation, reducing the risk of mathematical errors -- but correctly interpreting the results of an analysis can be even more challenging.  No one knows that better than Minitab's technical trainers. All of our trainers are seasoned statisticians... Continue Reading
You know that song "Once in a Lifetime," by Talking Heads?  The one where David Byrne keeps repeating "Same as it ever was"?   "Same as it never was" is more like it. We confront variation constantly.    Think about it. Did you spend exactly the same amount of time commuting to work today as you did yesterday? No? That's variation.    While these planes look identical, some variation exists. But... Continue Reading
Today is the annual Thanksgiving holiday in the United States, so it's a good opportunity to share some stories about successful projects that I've been thankful to learn and write about over the past few years.  I joined Minitab after spending many years as both a freelance and in-house science writer for various organizations and institutions. When I began working at Minitab, I wondered whether... Continue Reading
Manufacturers need to make items that meet a customer’s standards, or they’ll soon be out of business. That’s why quality engineers devote a good deal of time to making sure that processes are able to meet those standards.  The first step is to make sure your process is stable. After all, you can’t predict the performance of an unstable process. But you can predict and improve on a stable process.  I... Continue Reading
A few weeks ago, on National Pierogi Day, I explained how you could use Minitab Statistical Software to design an experiment that would let you assess the impact of different factors on the mushiness of pierogies. We created a 1/4 fraction factorial design, which let us look at the effects of five factors. We had to make a trade-off: this design would not let us look at how interactions between... Continue Reading
October 8 is National Pierogi Day. Not only is this a great opportunity to nosh on those cheese-and-potato-filled dumplings, but it’s also a good time to offer a simple kitchen-based example of what makes the statistical method called Design of Experiments so cool.  Let’s say you want to make pierogies that are as good as grandma’s, but yours are too mushy. You don’t know why. With so many inputs... Continue Reading
Can a 10-day forecast predict today's weather? I'm looking out the window at a slate-gray sky (again), and thinking about the last weather forecast I saw. That was a couple of days ago, but it called for sunny, warm weather. Not what I'm looking at now. On the other hand, it's the kind of weather that makes me glad to be inside analyzing data and doing statistics. Since the last weather forecast I... Continue Reading
The other day I needed to do some probability calculations without the usual technology on hand -- no computer, smart phone, or calculator. It was a great reminder of just how much I appreciate tools that make the work of analyzing data easier and faster. Anyone who's taken a statistics class that required you to do all calculations by hand recognizes the truth of a statement that someone posted... Continue Reading
Companies invest a great deal of time, effort, and money in Lean Six Sigma programs. So if you're doing a project, the expectations are probably high: companies that have made this investment expect good projects to challenge expectations, make processes better, and improve profitability. When you hear about projects that save companies like Motorola and General Electric millions of dollars, you... Continue Reading
Your Lean Six Sigma project resulted in tremendous process improvement. It's time to share the results. To help people understand your data quickly and clearly -- especially if they don’t know statistics -- you need graphs.Statistical software lets us use a wide array of graphs to display data, depending on what we want to convey. So why restrict yourself to pie or bar charts, when there are many... Continue Reading
Control charts are simple but very powerful tools that can help you determine whether a process is in control (meaning it has only random, normal variation) or out of control (meaning it shows unusual variation, probably due to a "special cause"). In an earlier post, I wrote about the common elements that all control charts share: upper and lower control limits, an expected variation region, and... Continue Reading
They say "variety is the spice of life," but when it comes to doing business, variation is not your friend. That's why we have control charts. One of these things is not like the others...is it common cause variation you can accept, or special variation that needs to be addressed? Control charts could tell you. We know that a little bit of variation is inevitable, but we tolerate it within... Continue Reading
Statistics can get pretty complicated, which is one reason why so many people are intimidated by the idea of data analysis. But even simple analyses can wind up having a big impact on a company's bottom line.You don't need an elephant gun to take care of a mosquito. Similarly, you don't want to devise a 15-factor, full-factorial designed experiment when a much simpler analysis can take care of the... Continue Reading
There's a scene in the movie Apocalypse Now where Captain Willard (Martin Sheen) is puzzling over what his commanders have asked him to do, and even why they're asking him to do it. As the movie progresses, it becomes clear that his project really hasn't been very well thought out. If the commanders in the film had been Lean Six Sigma Black Belts, I wonder how the narrative would have changed. I... Continue Reading
I recently came across a good post about fishbone diagrams on Christian Paulsen's Lean Leadership blog.  Fishbones (also called cause-and-effect, C&E or Ishikawa diagrams) help you brainstorm potential causes of a problem--and see relationships among potential causes. Brainstorming frequently gets a bad rap.  Some people have had bad experiences with brainstorming sessions that were too loose, and... Continue Reading