Blog posts and articles about the the statistical method called Design of Experiments in quality improvement.

Dear Readers,
As
2016 comes to a close, it’s time to reflect on the passage of time
and changes. As I’m sure you’ve guessed, I love statistics and
analyzing data! I also love talking and writing about it. In fact,
I’ve been writing statistical blog posts for over five years, and
it’s been an absolute blast. John Tukey, the renowned statistician,
once said, “The best thing about being a statistician... Continue Reading

If your work involves quality improvement, you've at least
heard of Design of Experiments (DOE). You probably know
it's the most efficient way to optimize and improve your process.
But many of us find DOE intimidating, especially if it's not a tool
we use often. How do you select an appropriate design, and ensure
you've got the right number of factors and levels? And after you've
gathered your... Continue Reading

Since the release of Minitab
Express in 2014, we’ve often received questions in technical
support about the differences between Express and Minitab 17.
In this post, I’ll attempt to provide a comparison between these
two Minitab products.
What Is Minitab 17?
Minitab 17 is an all-in-one graphical and statistical analysis
package that includes basic analysis tools such as hypothesis
testing,... Continue Reading

We’ve got a plethora of case studies showing how businesses from different
industries solve problems and implement solutions with data
analysis. Take a look for ideas about how you can use data analysis
to ensure excellence at your business!
Boston Scientific, one of the world’s leading developers of
medical devices, is just one organization who has shared their
story. A team at their Heredia,... Continue Reading

You’ve
performed multiple linear regression and have settled on a model
which contains several predictor variables that are statistically
significant. At this point, it’s common to ask, “Which variable is
most important?”
This question is more complicated than it first appears. For one
thing, how you define “most important” often depends on your
subject area and goals. For another, how you collect... Continue Reading

The college football season is here, and this raises a very
important question:
Is Alabama going to be undefeated when they win the national
championship, or will they lose a regular-season game along the
way?
Okay, so it's not a given that Alabama is going to win
the championship this year, but when you've won 4 of the last 7
you're definitely the odds-on favorite.
However, what if we wanted to take... Continue Reading

If you’re in the market for statistical software, there are many
considerations and more than a few options for you to evaluate.
Check out these seven questions to ask yourself before choosing
statistical software—your answers should help guide you towards the
best solution for your needs!
1. Who uses statistical software in your organization?
Are they expert statisticians, novices, or a mix of both?... Continue Reading

Design of Experiments (DOE) is the perfect tool to efficiently
determine if key inputs are related to key outputs. Behind the
scenes, DOE is simply a regression analysis. What’s not simple,
however, is all of the choices you have to make when planning your
experiment. What X’s should you test? What ranges should you select
for your X’s? How many replicates should you use? Do you need
center... Continue Reading

Design of Experiments is an extremely
powerful statistical method, and we added a DOE tool to the
Assistant in Minitab 17 to make it more accessible to more
people.
Since it's summer grilling season, I'm
applying the Assistant's DOE tool to outdoor
cooking. Earlier, I showed
you how
to set up a designed experiment that will let you optimize how
you grill steaks.
If you're not already using it and... Continue Reading

Design of Experiments (DOE) has a reputation for difficulty, and
to an extent, this statistical method deserves that
reputation. While it's easy to grasp the basic idea—acquire the
maximum amount of information from the fewest number of
experimental runs—practical application of this tool can
quickly become very confusing.
Even
if you're a long-time user of designed experiments, it's still easy
to... Continue Reading

Earlier this month, PLOS.org
published an article titled "Ten Simple Rules for Effective Statistical
Practice." The
10 rules are good reading for anyone who draws conclusions and makes decisions
based on data, whether
you're trying to extend the boundaries of scientific knowledge or
make good decisions for your business.
Carnegie Mellon University's
Robert E. Kass and several co-authors devised... Continue Reading

You often hear the data being
blamed when an analysis is not delivering the answers you wanted or
expected. I was recently reminded that the data chosen or collected
for a specific analysis is determined by the analyst, so there is
no such thing as bad data—only bad
analysis.
This made me think about the
steps an analyst can take to minimise the risk of producing
analysis that fails to answer... Continue Reading

by Laerte de Araujo Lima, guest blogger
The NBA's 2015-16 season will be one for the history books. Not
only was it the last season of Kobe Bryan,
who scored 60 points in his final game, but the Golden State
Warriors set
a new wins record, beating the previous record set by 1995-96
Chicago Bulls.
The
Warriors seem likely to take this season's NBA title, in large part
thanks to the performance of... Continue Reading

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 come up in many
different contexts in statistics—some advanced and complicated. In
mathematics, they're... Continue Reading

In my last post, 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 parameters in
16 runs.
Analyzing the Design
Now we'll examine the analysis of the DOE results after the
actual... Continue Reading

I used to work
in the manufacturing industry. Some processes were so complex that
even a very experienced and competent engineer would not
necessarily know how to identify the best settings for the
manufacturing equipment.
You could make a guess using a general idea of what should be
done regarding the optimal settings, but that was not sufficient.
You need very precise indications of the correct... Continue Reading

P values have been around for nearly a century and they’ve been
the subject of criticism since their origins. 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 science.
In March 2016, spurred on by the growing concerns, the American
Statistical Association (ASA) did... Continue Reading

Did you know that March is Women’s History Month? The
celebration was started in the 1980s by the U.S. government to pay
tribute to generations of influential women.
To celebrate, here’s a roundup of just some of the most
influential women in statistics:
Florence Nightingale
While Florence Nightingale is known as the founder of modern
nursing, you might not know that she is also a... Continue Reading

In the world of linear models, a hierarchical model contains all
lower-order terms that comprise the higher-order terms that also
appear in the model. For example, a model that includes the
interaction term A*B*C is hierarchical if it includes these terms:
A, B, C, A*B, A*C, and B*C.
Fitting the correct regression model can be as
much of an art as it is a science. Consequently, there's not always
a... Continue Reading

How deeply has statistical content from Minitab blog posts (or
other sources) seeped into your brain tissue? Rather than submit a
biopsy specimen from your temporal lobe for analysis, take this
short quiz to find out. Each question may have more than one
correct answer. Good luck!
Which
of the following are famous figure skating pairs, and which are
methods for testing whether your data follow a... Continue Reading