In my last post, I showed how to use Minitab Statistical
create an acceptance sampling plan by variables, using the
scenario of a an electronics company that receives monthly
shipments of LEDs that must have soldering leads that are at least
2 cm long. This time, we'll compare that plan with some other
The variables sampling plan we came up with to verify the... Continue Reading
Earlier, I shared an
overview of acceptance sampling. Now we'll look at how to do
acceptance sampling by variables, facilitated by the tools in
Minitab Statistical Software. If you're not already using it
and you'd like to follow along, you can get the free
30-day trial version.
In contrast to acceptance
sampling by attributes, where inspectors make judgment calls about
defective items,... Continue Reading
If you're just getting started in the world of quality
improvement, or if you find yourself in a position where you
suddenly need to evaluate the quality of incoming or outgoing
products from your company, you may have encountered the term
"acceptance sampling." It's a statistical method for evaluating the
quality of a large batch of materials from a small sample of items,
This is an era of massive data. A huge amount of data is being
generated from the web, from customer relations records but also
from sensors used in the manufacturing industry (semiconductor,
pharmaceutical, petrochemical companies and many other
Univariate Control charts
In the manufacturing industry, critical product characteristics
get routinely collected to ensure that all products... Continue Reading
of us have data stored in a database or file that we need to
analyze on a regular basis. If you're in that situation and you're
using Minitab Statistical Software, here's how you can save some
time and effort by automating the process.
When you're finished, instead of using File > Query
Database (ODBC) each time you want to perform analysis on
the most up-to-date set of data, you can add a... Continue Reading
Not long ago, I couldn’t abide
statistics. I did respect
it, but in much the same way a
gazelle respects a lion. Most of my early experiences with
statistics indicated that close encounters resulted in pain, so I
avoided further contact whenever possible.
So how is it that today I write about statistics? That’s simple:
it merely required completely reinventing the way I thought about
and approached... Continue Reading
There are many reasons why a distribution might not be
normal/Gaussian. A non-normal pattern might be caused by several
distributions being mixed together, or by a drift in time, or by
one or several outliers, or by an asymmetrical behavior, some
out-of-control points, etc.
I recently collected the scores of three different teams (the
Blue team, the Yellow team and the Pink team) after a laser... Continue Reading
P-values are frequently misinterpreted, which causes many
problems. I won't rehash those
problems here here since my colleague Jim Frost has
detailed the issues involved at some length, but the fact remains
that the p-value will continue to be one of the most frequently
used tools for deciding if a result is statistically
You know the old saw about "Lies, damned lies, and... Continue Reading
Having delivered training courses on
capability analyses with Minitab, several times, I have noticed
that one question you can be absolutely sure will be asked, during
the course, is: What is the difference between the Cpk
and the Ppk indices?
Ppk vs. Cpk indices
The terms Cpk and Ppk are often confused,
so that when quality or process engineers refer to the
Cpk index, they often actually intend to... Continue Reading
Back when I was an undergrad in
statistics, I unfortunately spent an entire semester of my life
taking a class, diligently crunching numbers with my TI-82, before
realizing 1) that I was actually in an Analysis of Variance (ANOVA)
class, 2) why I would want to use such a tool in the first place,
and 3) that ANOVA doesn’t necessarily tell you a thing about
Fortunately, I've had a lot more... Continue Reading
to this article published on Food Tank,
over 22 million pounds of food is wasted on college campuses each
year. Now that’s a lot of food waste!
Students all over the country are noticing excessive food waste
at their schools and are starting programs to bring awareness and
improve the problem. Naturally, many of these programs have roots
in Lean Six Sigma. In one example, a group of... Continue Reading
use statistics to arm ourselves with more information. That
information allows us to make more informed decisions. And the
sooner we can obtain this information, the better.
For example, suppose one of your manufacturing machines starts
to malfunction and makes your products out of spec. You don't want
to wait until the product reaches customers before you discover
this information. Then it's... Continue Reading
you ever wonder why statistical analyses and concepts often have
such weird, cryptic names?
One conspiracy theory points to the workings of a secret
committee called the ICSSNN. The International Committee for
Sadistic Statistical Nomenclature and Numerophobia was formed
solely to befuddle and subjugate the masses. Its mission: To select
the most awkward, obscure, and confusing name possible... Continue Reading
Control charts are a fantastic tool. These charts plot your
process data to identify common cause and special cause variation.
By identifying the different causes of variation, you can take
action on your process without over-controlling it.
Assessing the stability of a process can help you determine
whether there is a problem and identify the source of the problem.
Is the mean too high, too low,... Continue Reading
By Matthew Barsalou, guest
A problem must be understood before it can be properly
addressed. A thorough understanding of the problem is critical when
root cause analysis (RCA) and an RCA is necessary if an
organization wants to implement corrective actions that truly
address the root cause of the problem. An RCA may also be necessary
for process improvement projects; it is... Continue Reading
Easy access to the right tools makes any task easier. That
simple idea has made the Swiss Army knife essential for
adventurers: just one item in your pocket gives you instant access
to dozens of tools when you need them.
If your current adventures include analyzing data, the Editor
menu in Minitab
17 is just as essential.
Minitab’s Dynamic Editor Menu
Any job goes more smoothly when you have easy... Continue Reading
you know that November is World Quality Month? The American Society
for Quality is once again heading up this year’s festivities.
Throughout the month of November, ASQ will be promoting the use
of quality tools in businesses, communities, and institutions all
over the world. You can check it out at http://asq.org/world-quality-month/.
Here at Minitab, we’re also pretty excited about World... Continue Reading
In Part 5 of our series, we began the analysis of
the experiment data by reviewing analysis of covariance and
blocking variables, two key concepts in the design and
interpretation of your results.
250-yard marker at the Tussey Mountain Driving Range, one of the
locations where we conducted our golf experiment. Some of the
golfers drove their balls well beyond this 250-yard maker during a
few of... Continue Reading
By Matthew Barsalou, guest
Teaching process performance and capability studies is easier
when actual process data is available for the student or trainee to
practice with. As I have previously
discussed at the Minitab Blog, a catapult can be used to
generate data for a capability study. My last blog on using a
catapult for this purspose was several years ago, so I would like
to revisit... Continue Reading
Minitab is the leading provider of software and services for quality
improvement and statistics education. More than 90% of Fortune 100 companies
use Minitab Statistical Software, our flagship product, and more students
worldwide have used Minitab to learn statistics than any other package.
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