The DMAIC methodology for completing quality improvement projects divides project work into five phases: define, measure, analyze, improve, and control. It’s also probably the most well-known and most used project methodology for projects that focus on improving an existing process. (Many other methodologies exist, such as DMADV, which focuses on using quality improvement techniques to create a new product of process design.)

Franciscan Hospital for Children, a hospital in Brighton, Mass., that specializes in the care of children with special health care needs, recently completed a project...

A t-test is one of the most frequently used procedures in statistics.

But even people who frequently use t-tests often don’t know exactly what happens when their data are wheeled away and operated upon behind the curtain using statistical software like Minitab.

It’s worth taking a quick peek behind that curtain.

Because if you know how a t-test works, you can understand what your results really mean. You can also better grasp why your study did (or didn’t) achieve “statistical significance.”

In fact, if you’ve ever tried to communicate with a distracted teenager, you already have experience with...

Yesterday I wrote about how paleontologist Zhijie Jack Tseng used 3D surface plots created in Minitab Statistical Software to look at how the skulls of hyenas and some extinct dogs with similar dining habits fit into a spectrum of possible skull forms that had been created with 3D modelling techniques.

What's interesting about this from a data analysis perspective is how Tseng took tools commonly used in quality improvement and engineering and applied them to his research into evolutionary morphology.

We used Tseng's data to demonstrate how to create and explore 3D surface plots yesterday, so...

A while back my colleague Jim Frost wrote about applying statistics to decisions typically left to expert judgment; I was reminded of his post this week when I came across a new research study that takes a statistical technique commonly used in one discipline, and applies it in a new way. 

The study, by paleontologist Zhijie Jack Tseng, looked at how the skulls of bone-cracking carnivores--modern-day hyenas--evolved. They may look like dogs, but hyenas in fact are more closely related to cats. However, some extinct dog species had skulls much like a hyena's. 

Tseng analyzed data from 3D...

I recently had the opportunity to talk with Ken Jones, professor of operations and supply chain management at Indiana State University, about a business process improvement course he teaches at the university. The course covers a variety of Lean Six Sigma tools and techniques and gives students the opportunity to team with local businesses to complete real quality improvement projects. Upon successful completion of the class, students even become certified green belts.

One item we talked about was how valuable the experiential component of the projects can be for students, especially...

When you learned statistics, most of what you learned was centered around the Normal distribution.  Maybe you became close friends and you later found out his birth name was Gaussian, but either way you probably just call him Normal.

You might know Normal’s a pretty popular guy with plenty of relationships with other distributions.  There are some obvious connections, like how eNormal is Lognormal, but I thought I’d share some less obvious ones. 

You probably already know that by subtracting his mean and dividing by his standard deviation you get Standard Normal.

What if you squared Standard...

by Alex Orlov, guest blogger

While it has been called the "million-dollar methodology" for the significant investment sometimes required to deliver results, Six Sigma has a wealth of practices that can be adapted to small and medium industries, home businesses and even personal finances. 

Organizations have used Six Sigma as a reliable part of the quality improvement process since 1986. And while a large Six Sigma project could cost anything from $1,000 to $1 million in work-hours and other resources, the results of such projects often far outweigh the investment. In addition to the direct...

After you have fit a linear model using regression analysis, ANOVA, or design of experiments (DOE), you need to determine how well the model fits the data. To help you out, Minitab statistical software presents a variety of goodness-of-fit statistics. In this post, we’ll explore the R-squared (R2 ) statistic, some of its limitations, and uncover some surprises along the way. For instance, low R-squared values are not always bad and high R-squared values are not always good!

What Is Goodness-of-Fit for a Linear Model?

Linear regression...

Previously I wrote about using a decision matrix to help make a decision. Matrices are nice tools for collecting your thoughts and visualizing a decision. But complex decisions could involve collecting and synthesizing input from a number of different people.

Quality Companion (Minitab's process improvement software) uses ballots to let team members record their input to a decision matrix. If you’ve already made the matrix, setting up the ballot is easy. The ballot simplifies data collection and organization, even among team members who are dispersed in space and time. You can follow along in...

I spend a 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 life. That’s the world of an engineer.

For this reason, you can imagine my surprise when my husband called me at work on a bright, sunny June day in 2009 to tell me that our 4-year-old daughter had been diagnosed with Lyme disease. That, to me, seemed completely improbable. We live in a development in suburbia.  Our children don’t play deep in the woods. We don’t hike in the woods. In accordance with the...

Over on the Indium Corporation's blog, Dr. Ron Lasky has been sharing some interesting ideas about using the Weibull distribution in electronics manufacturing. For instance, check out this discussion of how dramatically an early first-failure can affect an analysis of a part or component (in this case, an alloy used to solder components to a circuit board). 

This got me thinking again about all the different situations in which the Weibull distribution can help us make good decisions. The main reason Weibull is so useful is that it's very flexible in fitting different types of data, because it...

For providers like Riverview Hospital Association, serving Wisconsin Rapids, Wis. and surrounding areas, recent changes in the U.S. healthcare system have placed more emphasis on improving the quality of care and increasing patient satisfaction. “In this era of healthcare reform, it is even more essential for providers to have a systematic method to improve the way care is delivered,” says Christopher Spranger, director of Lean Six Sigma and Quality Improvement at Riverview Hospital Association. “We have had a Lean Six Sigma program in place for four years, and we are continuously working on...

Failure to properly calibrate this machine will result in defective rock and roll. 

In my last post, I imagined using the example of a rock and roll band -- the Zero Sigmas -- to explain Pareto charts to my music-loving but statistically-challenged boss. I showed him how easy it was to use a Pareto chart to visualize defects or problems that occur most often, using the example of various incidents that occurred on the Zero Sigmas last tour.  

The Pareto chart revealed that starting performances late was far and away the Zero Sigmas' most frequent "defect," one that occurred every single night of...

In a previous post, I wrote about how the field of statistics is more important now than ever before due to the modern deluge of data. Because you’re reading Minitab's statistical blog, I’ll assume that we’re in agreement that statistics allows you to use data to understand reality. However, I’d also bet that you’re picturing important but “typical” statistical studies, such as studies where Six Sigma analysts determine which factors affect product quality. Or perhaps medical studies, like determining the effectiveness of flu shots.

In this post,...

Normally, I tell you about ways to practice with Minitab Statistical Software so that you can boost your confidence with statistical analysis. But over the last few days in my house, we’ve been planning some activities for the family. That planning has given me a chance to have some fun with Quality Companion.

Quality Companion is a substantial piece of software: everything that you need to manage a quality improvement project in one application. Quality Companion provides project management tools so that you can make and communicate decisions.

My favorite tools in Quality Companion, with...

We usually think of games as a distraction—just something we do for fun. However, growing evidence suggests that games can do much more, especially when it comes to learning in a classroom setting.

Because statistics is a topic that doesn’t come easily to most, using properly designed games to teach statistics can become a valuable tool to spark interest and help explain difficult concepts.

So what kinds of “properly designed” games are we talking about here? Not traditional board games like Monopoly or Chutes and Ladders, but interactive computer games—the types of games younger generations...

Unless you’re 3 years old, you probably can’t have things just the way you want them all the time.  

You can’t always have peanut butter and ranch dressing on your toast. Or ketchup on your pineapple. Or sugar sprinkles on your peas.

But there is one small arena in life over which you can still exert your control. 

Tools > Options in Minitab's statistical software allows you to change selected default settings in the software, without having to throw a temper tantrum first.

This powerful, underutilized feature in Minitab may save you from the inconvenience of having to change a default setting...

I'm in the airport at Indianapolis, waiting to go home after three exciting days at the 2013 American Society for Quality World Conference.  As I write this, it's Wednesday evening after the conference has closed, and it turns out my flight has been delayed.

This could give me ample opportunity to muse about the quality issues that might keep me from reaching central Pennsylvania tonight. But I'm kind of pumped up, so I'm more interested in thinking about what I've experienced and seen over the past few days. This is the kind of event that makes you want to keep focusing on the positive, not...

As we said in yesterday’s post, it’s been exciting for Minitab to be a supporter of the ASQ World Conference on Quality and Improvement taking place this week in Indianapolis. There have been many great sessions and an abundance of case studies shared that highlight how quality teams worldwide are improving the performance of their businesses.

One session that generated a lot of interest from the conference participants was conducted by Minitab trainers Lou Johnson, Daniel Griffith and Jim Colton.

Their presentation, Sampling Plan for Expanded Gage R&R Studies, covered Gage R&R studies and how...

The 2013 ASQ World Conference is taking place this week in Indianapolis, Indiana, and it's been a treat to see how our software was used in the projects highlighted in many of the presentations. As a supporter of the conference, a key event for quality practitioners around the world, Minitab was proud to sponsor one of the presentations that seemed to get a lot of attendees talking. Scott Sterbenz, a Six Sigma leader from Ford Motor Company, delivered a presentation entitled "Leveraging Designed Experiments for Success," which explained how to make designed experiments succeed with examples...