In Part 1 of this blog series, I
compared Six Sigma to a diamond because both are valuable, have
many facets and have withstood the test of time. I also explained
how the term “Six Sigma” can be used to summarize a variety of
concepts, including philosophy, tools, methodology, or metrics. In
this post, I’ll explain short/long-term variation and
between/within-subgroup variation and how they help... Continue Reading
Welcome to the Hypothesis Test Casino! The featured game of the
house is roulette. But this is no ordinary game of
roulette. This is p-value roulette!
Here’s how it works: We have two roulette wheels, the Null wheel
and the Alternative wheel. Each wheel has 20 slots (instead of the
usual 37 or 38). You get to bet on one slot.
What happens if the ball lands in the slot you bet on? Well,
that depends... Continue Reading
A recent discussion on the Minitab
Network on LinkedIn pertained to the I-MR chart. In the
course of the conversation, a couple of people referred to it as
"The Swiss Army Knife of control charts," and that's a pretty great
description. You might be able to find more specific tools for
specific applications, but in many cases, the I-MR chart gets the
job done quite adequately.
When you're... Continue Reading
now I’m enjoying my daily dose of morning joe. As the steam rises
off the cup, the dark rich liquid triggers a powerful enzyme
cascade that jump-starts my brain and central nervous system,
delivering potent glints of perspicacity into the dark crevices of
my still-dormant consciousness.
Feels good, yeah! But is it good for me? Let’s see what the
Drinking more than 4 cups of coffee... Continue Reading
Statistics can be challenging, especially if you're not
analyzing data and interpreting the results every day. Statistical
software makes things easier by handling the arduous
mathematical work involved in statistics. But ultimately, we're
responsible for correctly interpreting and communicating what the
results of our analyses show.
The p-value is probably the most frequently cited
statistic. We... Continue Reading
As a person who loves baking (and eating) cakes, I find it
bothersome to go through all the effort of baking a cake when the
end result is too dry for my taste. For that reason, I decided to
use a designed experiment in Minitab to help me reduce the moisture
loss in baked chocolate cakes, and find the optimal settings of my
input factors to produce a moist baked chocolate cake. I’ll share
the... Continue Reading
by Matthew Barsalou, guest
The old saying “if it walks like a duck, quacks like a duck and
looks like a duck, then it must be a duck” may be appropriate in
bird watching; however, the same idea can’t be applied when
observing a statistical distribution. The dedicated ornithologist
is often armed with binoculars and a field guide to the local birds
and this should be sufficient. A... Continue Reading
Have you ever wanted to know the odds of something happening, or
It's the kind of question that students are frequently asked to
calculate by hand in introductory statistics classes, and going
through that exercise is a good way to become familiar with the
mathematical formulas the underlie probability (and hence, all of
But let's be honest: when class is over, most... Continue Reading
In its industry guidance to companies that manufacture drugs and
biological products for people and animals, the Food and Drug
Administration (FDA) recommends three stages for process
my last post covered
statistical tools for the Process Design stage, here we will
focus on the statistical techniques typically utilized for the
second stage, Process Qualification.
Stage 2: Process... Continue Reading
In my last post on
DMAIC tools for the Define phase, we reviewed various graphs
and stats typically used to define project goals and
customer deliverables. Let’s now move along to the tools you can
use in Minitab
Statistical Software to conduct the Measure phase.
Measure Phase Methodology
The goal of this phase is to measure the process to
determine its current performance and quantify the problem.... Continue Reading
Process validation is vital to the success of companies that
manufacture drugs and biological products for people and animals.
According to the FDA guidelines published by the U.S. Department of
Health and Human Services:
“Process validation is defined as
the collection and evaluation of data, from the process design
state through commercial production, which establishes scientific
evidence that a... Continue Reading
by Matthew Barsalou, guest blogger
The great Dr. Seuss tells of Mr. Plunger, who is the custodian
at Diffendoofer School on the corner of Dinkzoober and Dinzott in
the town of Dinkerville. The good Mr. Plunger “keeps the whole school clean” using a
Unfortunately, Dr. Seuss fails to tell us where the
supper-zooper-flooper-do came from and if the production process
was... Continue Reading
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
by Matt Barsalou, guest blogger
I know that Thanksgiving is always on the last Thursday in
November, but somehow I failed to notice it was fast approaching
until the Monday before Thanksgiving. This led to frantically
sending a last-minute invitation, and a hunt for a turkey.
I live in Germany and this greatly complicated the matter. Not
only is Thanksgiving not celebrated, but also actual turkeys... Continue Reading
again, with the arrival of autumn, it's time for a flu shot.
I get a flu shot every year even though I know they’re not
perfect. I figure they’re a relatively easy and inexpensive way to
reduce the chance of having a miserable week.
I’ve heard on various news media that their effectiveness is
about 60%. But what does 60% effectiveness mean, exactly? How much
does this actually reduce the... Continue Reading
In Part 1 of this
blog series, I wrote about how statistical inference uses data
from a sample of individuals to reach conclusions about the whole
population. That’s a very powerful tool, but you must check your
assumptions when you make statistical inferences. Violating any of
these assumptions can result in false positives or false negatives,
thus invalidating your results.
The common data... Continue Reading
If you’re not a statistician, looking through statistical output
can sometimes make you feel a bit like Alice in
Wonderland. Suddenly, you step into a fantastical world
where strange and mysterious phantasms appear out of nowhere.
For example, consider the T and P in your t-test results.
“Curiouser and curiouser!” you might exclaim, like Alice, as you
gaze at your output.
What are these values,... Continue Reading
Statistical inference uses data from a sample of individuals to
reach conclusions about the whole population. It’s a very
powerful tool. But as the saying goes, “With great
power comes great responsibility!” When attempting to make
inferences from sample data, you must check your assumptions.
Violating any of these assumptions can result in false positives or
false negatives, thus invalidating... Continue Reading
Data mining can be helpful in the exploratory phase of an
analysis. If you're in the early stages and you're just figuring
out which predictors are potentially correlated with your response
variable, data mining can help you identify candidates. However,
there are problems associated with using data mining to select
In my previous post, we used data mining to settle on
the following... Continue Reading
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