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Applying Six Sigma to a Small Operation, Part 2

In my previous post, I shared a case study of how a small bicycle-chain manufacturing company in India used the DMAIC approach to Six Sigma to reverse declining productivity.

After completing the Define, Measure, and Analysis phases, the team had identified the important factors in the bushing creation process. Armed with this knowledge, they were now ready to make some improvements.

The Improve Phase

In the Improve phase, the team applied a statistical method called Design of Experiments (DOE) to optimize the important factors they'd identified in the initial phases.

Most of us learn in school...

Lessons in Quality During a Long and Strange Journey Home

I didn’t expect that our family trip to Florida would end with me driving a plane load of passengers nearly 200 miles to their homes, but it did.

Yes, it was a long and strange journey home. A journey that started in the tropical warmth of southern Florida and ended the next morning in central Pennsylvania, which felt like the arctic wastelands thanks to the dreaded polar vortex.

During this journey, I didn’t just experience temperature extremes, but also extremely different levels in the quality of customer care. Working at Minitab, I'm very aware of the quality of service because quality...

Merge Data as You Open It

Did you know about the Minitab Network group on LinkedIn? It’s the one managed by Eston Martz, of Minitab blog fame. I like to see what the members are talking about, which recently got me into some discussions about Raman spectroscopy data.

Not having much experience with Raman spectroscopy data, I thought I’d learn more about it and found the RRUFFTM Project.

The idea is that if you have a Raman device, you can analyze a mineral sample and compare your results to information in the database so that you can identify your mineral. Not having a Raman device, the site is still exciting to me...

Applying Six Sigma to a Small Operation

Using data analysis and statistics to improve business quality has a long history. But it often seems like most of that history involves huge operations. After all, Six Sigma originated with Motorola, and became adopted by thousands of other businesses after it was adopted by a little-known outfit called General Electric.

There are many case studies and examples of how big companies used Six Sigma methods to save millions of dollars, slash expenses, and improve quality...but when they read about the big dogs getting those kind of results, a lot of folks hear a little voice in their heads...

A Statistical History of the Super Bowl

Super Bowl Sunday is right around the corner! But instead of trying to break down and predict the outcome of the game (which will likely come down to turnovers, which are impossible to predict), I’m going to look at some different statistics from previous Super Bowls. How many close games have there been? How much has the price for a 30-second add increased over the years? Which state has hosted the Super Bowl the most times? I’ll look at them all!

The Actual Game

First, I’m going to look at different things that have happened in the game. Five of the last 6 Super Bowls have been decided...

Winning a Super Bowl Grid Pool: Frequency of Score Combinations in the NFL

It has come to my attention recently that amidst the fun of attending Super Bowl parties and watching the 2nd-most viewed sporting event on earth there are some people—seedy characters with questionable pasts, I'm sure—who are betting on the game! 

Now, as gambling on sporting events is highly regulated and illegal in almost every state, I'm confident that reports of this are overblown and that the fine, upstanding readers of this blog are not among those taking part in such an activity.

But if you happen to live in an area where such things are legal and you choose to participate, then you...

Setting the Stage: Accounting for Process Changes in a Control Chart

When looking at a control chart, it’s important to know that the data we are looking at is accurate. Let’s face it, if the control limits we are looking at don’t really reflect what’s actually happening in our process, what does it matter if our points fall within the limits, or a little bit outside?

Let’s take a trip down to the widget factory, where widgets are being produced in all shapes and sizes. We’re going to take a look at one particular widget, and the time it takes for that particular widget to be produced (in minutes).

In a Minitab Statistical Software datasheet, we have two months...

Minitab illustrates the need for fire safety

The January/February issue of Men’s Health includes an article by Michael Perry with photographs by Eric Ogden titled “Voices from the Flames.” The article contains a lot of statistics that I didn’t know about fires in contemporary America. As a statistician, I like articles with statistics. While this article included a satisfying number of statistics, graphs that would make them easy to understand were absent. So in the interests of communicating the importance of fire safety, I thought I’d take a minute to make some graphs myself, inspired by some of the statistics that Perry uses....

Regression Analysis: How to Interpret S, the Standard Error of the Regression

R-squared gets all of the attention when it comes to determining how well a linear model fits the data. However, I've stated previously that R-squared is overrated. Is there a different goodness-of-fit statistic that can be more helpful? You bet!

Today, I’ll highlight a sorely underappreciated regression statistic: S, or the standard error of the regression. S provides important information that R-squared does not.

What is the Standard Error of the Regression (S)?

S becomes smaller when the data points are closer to the line.

In the regression output for Minitab statistical software, you can find...

Analyzing “Luck” in College Basketball: Part 1

College basketball stat guru Ken Pomeroy uses advanced metrics to rank every NCAA Division I basketball team. Amongst the numerous statistics he tracks is one called "Luck."

This statistic is calculated as the difference between a team’s actual winning percentage, and what one would expect their winning percentage to be based on how many points they score and how many they allow.

What it really boils down to is close games. In theory, you should win about half of your close games and lose half. If you win most of your close games, you'll have a high luck statistic in the Pomeroy Ratings. Lose...

Creating a Shatterproof Process: Students Use Six Sigma to Improve Window Manufacturing

I had the opportunity to speak with a great group of students from the New Jersey Governor’s School of Engineering and Technology—a summer program for high-achieving high school students. Students in the program complete a set of challenging courses while working in small groups on real-world research and design projects that relate to the field of engineering. Governor’s School students are mentored by professional engineers as well as Rutgers University honors students and professors, and they often work with companies and organizations to solve real engineering problems.

The team of students...

A Statistical Look at How Turnovers Impacted the NFL Season

“Turnovers are like ex-wives. The more you have, the more they cost you.” – Dave Widell, former Dallas Cowboys lineman

It doesn’t take witty insight from a former NFL player to realize how big an impact turnovers can have in a football game. Every time an announcer talks about “Keys to the Game,” winning the turnover battle is one of them. And as Cowboys fans know all too well, an ill-timed interception can ruin not only your chances of winning that game, but it can ruin your entire season, too.

But hold on a minute. A few weeks ago, Andrew Luck and the Colts proved that you could still win a...

How High Should R-squared Be in Regression Analysis?

Just how high should R2 be in regression analysis? I hear this question asked quite frequently.

Previously, I showed how to interpret R-squared (R2). I also showed how it can be a misleading statistic because a low R-squared isn’t necessarily bad and a high R-squared isn’t necessarily good.

Clearly, the answer for “how high should R-squared be” is . . . it depends.

In this post, I’ll help you answer this question more precisely. However, bear with me, because my premise is that if you’re asking this question, you’re probably asking the wrong question. I’ll show you which questions you should...

Use the Minitab Assistant to Choose a Graph

Everyone loves Minitab’s Assistant. My favorite bit, as I’ve shown with the Gage R&R Study, is the way that the Assistant puts all the results you need into reports that are easy to understand and present. But it’s also pretty neat that before you ever choose what to do in Minitab, the Assistant is ready to help you. Let’s take a closer look at the Assistant's Graphical Analysis tools.

Help Me Choose

Choose Assistant > Graphical Analysis and the most prominent thing you’ll see is a question:

But you’re not left with just the three objectives. Select "graph variables over time," and before you...

Quantum Estimates: Where Angels Fear to Tread

This close to the holidays, it’s hard to stay focused on work.

I should be writing a post about useful estimation tools for quality statistics. But all those yuletide carols about hosts of angels singing from on high have distracted me.

Alas, I’ve fallen into the clutches of one of the world’s oldest estimation problems, posed centuries ago by medieval scholars:

Just how many heavenly angels can dance simultaneously on the point of a pin?

The answer to this question assumes that you believe in the existence of pins, of course.

Estimation in the Middle Ages: Ask Your Doctor

Over the centuries, a...

Does Peyton Manning Play Worse in Cold Weather?

If you’re a believer that Peyton Manning plays worse in cold weather, the last few weeks have only strengthened your resolve. In 3 of his last 4 games, he’s played in temperatures below 40 degrees, and come out with a record of 1-2. In his other “warm weather” games this season, Manning has a record of 10-1. This continues a theme that has plagued Manning his entire career, that he underperforms when the temperature goes south.

But will the statistics support that theory?

Peyton’s Statistics in Cold Weather Games

Thanks to an article by the Mile High Report, I was able to obtain data on every...

Is There a World Cup "Group of Death"?

Much is made following the World Cup draw every four years over which group is the “group of death.”  This is generally considered to be a really difficult group that is tough to advance from, although there is no true definition (more on that below).

First, for readers not familiar with World Cup groups, a brief explanation of how teams are “grouped” in the World Cup is in order.  Thirty-two teams qualify to compete, and they are placed into eight different groups labeled A-H, with each having a predetermined “top” team.  In the group stage of the World Cup, each team plays the other three...

Regression Analysis Tutorial and Examples

I’ve written a number of blog posts about regression analysis and I think it’s helpful to collect them in this post to create a regression tutorial. I’ll supplement my own posts with some from my colleagues.

This tutorial covers many aspects of regression analysis including: choosing the type of regression analysis to use, specifying the model, interpreting the results, determining how well the model fits, making predictions, and checking the assumptions. At the end, I include examples of different types of regression analyses.

If you’re learning regression analysis right now, you might want to...

Fix Problems in Regression Analysis with Partial Least Squares

Face it, you love regression analysis as much as I do. Regression is one of the most satisfying analyses in Minitab: get some predictors that should have a relationship to a response, go through a model selection process, interpret fit statistics like adjusted R2 and predicted R2, and make predictions. Yes, regression really is quite wonderful.

Except when it’s not. Dark, seedy corners of the data world exist, lying in wait to make regression confusing or impossible. Good old ordinary least squares regression, to be specific.

For instance, sometimes you have a lot of detail in your data, but not...

Will Playoffs Make College Football's Regular Season Less Exciting?

If you're scared this is what the playoff will look like, just remind yourself that Georgia Southern beat Florida this year without completing a pass.

Auburn beat Alabama this past weekend in one of the most incredible endings you’ll ever see. The stakes couldn't have been higher. With the defeat, Alabama lost any realistic shot at playing for the national championship this year.

However, if this defeat had occurred next year, the loss would mean absolutely nothing to Alabama, at least in terms of playing for a national championship. If four teams were selected to compete in a playoff, Alabama...