Suppose that you plan to source a substantial amount of parts or
subcomponents from a new supplier. To ensure that their quality
level is acceptable to you, you might want to assess the capability
and Cpk indices) of their manufacturing processes and check
whether their critical process parameters are fully under control
control charts). If you are not sure about the efficiency... 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.
your current adventures include analyzing data, the multifaceted
Editor menu in Minitab Statistical
Software is just as essential.
Minitab’s Dynamic Editor Menu
Whether you’re... Continue Reading
It's a very exciting time at Minitab's offices around the world
because we've just announced the availability of
Minitab® 18 Statistical Software.
is everywhere today, but to use it to make sound, strategic
business decisions, you need to have tools that turn that data into
knowledge and insights. We've designed Minitab 18 to do
We've incorporated a lot of new
features, made some... Continue Reading
Before cutting an expensive piece of granite for a countertop, a
good carpenter will first confirm he has measured correctly. Acting
on faulty measurements could be costly.
no measurement system is perfect, we rely on such systems to
quantify data that help us control quality and monitor changes in
critical processes. So, how do you know whether the changes you see
are valid and not just the... Continue Reading
The 1949 film A Connecticut Yankee in King Arthur's
Court includes the song “Busy Doing Nothing,” and this
could be written about the
Null Hypothesis as it is used in statistical
The words to the song go:
We're busy doin' nothin'Workin' the whole day through
Tryin' to find lots of things not to do
And that summarises the role of
the Null Hypothesis perfectly. Let me explain why.
What's... Continue Reading
Rare events inherently occur in all kinds of
processes. In hospitals, there are medication errors, infections,
patient falls, ventilator-associated pneumonias, and other rare,
adverse events that cause prolonged hospital stays and increase
But rare events happen in many
other contexts, too. Software developers may need to track errors
in lines of programming code, or a quality... Continue Reading
Users often contact Minitab technical support to ask how the
software calculates the control limits on control charts.
A frequently asked question is how the control limits are
calculated on an
I-MR Chart or Individuals Chart. If Minitab plots the upper and
lower control limits (UCL and LCL) three standard deviations above
and below the mean, why are the limits plotted at values other than
3 times... Continue Reading
One highlight of writing for and editing the Minitab Blog is the
opportunity to read your responses and answer your questions.
Sometimes, to my chagrin, you point out that we've made a mistake.
However, I'm particularly grateful for those comments, because it
permits us to correct inadvertent errors.
feared I had an opportunity to fix just such an error when I saw
this comment appear on one of... Continue Reading
As someone who has collected and analyzed real data for a
living, the idea of using simulated data for a Monte Carlo
simulation sounds a bit odd. How can you improve a real product
with simulated data? In this post, I’ll help you understand the
methods behind Monte Carlo simulation and walk you through a
simulation example using Companion by Minitab.
Companion by Minitab is a software platform that... Continue Reading
Choosing the right type of subgroup in a control chart is
crucial. In a rational subgroup, the variability within a subgroup
should encompass common causes, random, short-term variability and
represent “normal,” “typical,” natural process variations, whereas
differences between subgroups are useful to detect drifts in
variability over time (due to “special” or “assignable” causes).
Variation within... Continue Reading
shopping. For some, it's the most dreaded household activity. For
others, it's fun, or perhaps just a “necessary evil.”
Personally, I enjoy it! My co-worker, Ginger, a content manager
here at Minitab, opened my eyes to something that made me love
grocery shopping even more: she shared the data behind her family’s
shopping trips. Being something of a data nerd, I really geeked out
over the... Continue Reading
Earlier, I wrote about the
different types of data statisticians typically encounter. In
this post, we're going to look at why, when given a choice in the
matter, we prefer to analyze continuous data rather than
categorical/attribute or discrete data.
As a reminder, when we assign something to a group or give it a
name, we have created attribute or
categorical data. If we count something,
like... Continue Reading
You run a capability analysis
and your Cpk is bad. Now what?
First, let’s start by defining
what “bad” is. In simple terms, the smaller the Cpk, the more
defects you have. So the larger your Cpk is, the
practitioners use a Cpk of 1.33 as the gold standard, so we’ll
treat that as the gold standard here, too.
Suppose we collect some data and run a capability analysis using
In Part 1 of Gauging Gage, I looked at how adequate a
sampling of 10 parts is for a Gage R&R Study and providing
some advice based on the results.
Now I want to turn my attention to the other two factors in the
standard Gage experiment: 3 operators and 2 replicates.
Specifically, what if instead of increasing the number of parts in
the experiment (my previous post demonstrated you would need... Continue Reading
by Kevin Clay, guest blogger
In transactional or service processes, we often deal with
lead-time data, and usually that data does not follow the normal
Consider a Lean Six Sigma project to reduce the lead time
required to install an information technology solution at a
customer site. It should take no more than 30 days—working 10 hours
per day Monday–Friday—to complete, test and... Continue Reading
"You take 10 parts and have 3 operators measure each 2
This standard approach to a Gage R&R experiment is so
common, so accepted, so ubiquitous that few people ever question
whether it is effective. Obviously one could look at whether
3 is an adequate number of operators or 2 an adequate number of
replicates, but in this first of a series of posts about
"Gauging Gage," I want to look at... Continue Reading
Everyone who analyzes data regularly has the experience of
getting a worksheet that just isn't ready to use. Previously I
wrote about tools you can use to
clean up and eliminate clutter in your data and
reorganize your data.
In this post, I'm going to
highlight tools that help you get the most out of messy data by
altering its characteristics.
Know Your Options
Many problems with data don't become... Continue Reading
You've collected a bunch of
data. It wasn't easy, but you did it. Yep, there it is, right
there...just look at all those numbers, right there in neat columns
and rows. Congratulations.
I hate to ask...but what are you
going to do with your data?
If you're not sure precisely
what to do with the data you've got, graphing it is a
great way to get some valuable insight and direction. And a good
graph to... Continue Reading
In my last post, I wrote about
making a cluttered data set easier to work with by removing
unneeded columns entirely, and by displaying just those columns you
want to work with now. But
too much unneeded data isn't always the problem.
What can you do when someone
gives you data that isn't organized the way you need it to be?
That happens for a variety of
reasons, but most often it's because the... Continue Reading
Isn't it great when you get a set of data and it's perfectly
organized and ready for you to analyze? I love it when the people
who collect the data take special care to make sure to format it
consistently, arrange it correctly, and eliminate the junk,
clutter, and useless information I don't need.
never received a data set in such perfect condition, you say?
Yeah, me neither. But I can... Continue Reading
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