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
I have two young children, and I
work full-time, so my adult TV time is about as rare as finding a
Kardashian-free tabloid. So I can’t commit to just any TV
show. It better be a good one. I was therefore extremely
excited when Netflix analyzed viewer
data to find out at what point
watchers get hooked on the first season of various
they identified the episode at which 70% of...Continue Reading
Monte Carlo simulation has all kinds of
useful manufacturing applications. And - in celebration of
Pi Day - I thought it would be
apropos to show how you can even use Monte Carlo simulation to
estimate pi, which of course is the mathematical constant that
represents the ratio of a circle’s circumference to its diameter.
For our example, let’s start with a circle of radius 1 inscribed
within a... Continue Reading
We like to host webinars, and our customers and prospects
like to attend them. But when our webinar vendor moved from a
pay-per-person pricing model to a pay-per-webinar pricing model, we
wanted to find out how to maximize registrations and thereby
minimize our costs.
We collected webinar data on the following variables:
Day of week
Time of day – 11 a.m. or 2 p.m.
Newsletter promotion –... Continue Reading
We cannot improve what we cannot measure. Therefore, it is
critical that we conduct a measurement systems analysis (MSA)
before we start analyzing our data to make any kind of
When conducting an MSA for continuous measurements, we typically
using a Gage R&R Study. And in these Gage R&R Studies,
we look at output such as the percentage
study variation (%Study Var, or %SV) and the Number...Continue Reading
"Do it myself!”
If only I had a nickel for every time I heard that phrase from
my toddler in a given day. From throwing away trash, to putting
frozen waffles in the toaster, to feeding the dog, I hear it so
often that I could possibly retire with all the nickels I’d
And of course, I hear this proclamation every single time my
2-year-old puts on her shoes.
happens when a toddler tries to... Continue Reading
When I think about the Central Limit Theorem (CLT), bunnies and
dragons are just about the last things that come to mind. However,
that’s not the case for Shuyi Chiou, whose playful CreatureCast.org
animation explains the CLT using both fluffy and fire-breathing
Per the article that accompanied this video in
The New York Times:
real-world observations can be approximated by, and... Continue Reading
Measurement systems analysis (MSA) is essential to the success
of any data analysis. If you cannot rely on the tool you’re using
to take measurements, then why bother collecting data to begin
with? It would be like trying to lose weight while relying on a
scale that doesn’t work. What’s the point in weighing yourself?
Minitab Statistical Software offers many types of tools that you
can use to... Continue Reading
In my last
post, I used U.S. Census Bureau data and correlation to reveal
that people living in colder, more crowded states typically make
more money. I’m sure there is some rationale to support this
conclusion, but I’ll leave that explanation up to the
economists. Meanwhile, let's you and me move on to more
Once I discovered there was correlation between income and
other census data,... Continue Reading
I recently read an article about how the United States median
household income has declined the last two years in a row.
While that should make most of us as joyful as
a vegetarian who just won a lifetime supply of beef
jerky, there are some states that have median household incomes
well above the norm.
So, any guesses as to which state is the best at over $70K, and
which is the worst at nearly... Continue Reading
to remember what the alpha-level, p-value, and confidence
interval all mean for a hypothesis test—and how they relate to
one another—can seem about as daunting as Dorothy’s trek down the
yellow brick road.
Rather than sitting through a semester of Intro Stats, let's get
right to the point and explain in clear language what all these
statistical terms mean and how they relate to one another.
Wh... Continue Reading
A statistician walks into a party. The host looks up and
says “Welcome! Let me introduce you to
everyone. This is John, Jeff, Jill, another Jeff,
Petra, Porter, Paxtyn and Chris.” The statistician declares, “I
love parties that exhibit properties of the Pareto
The host—not a statistician—slowly turns and walks away,
befuddled and bewildered.
True story? Almost, except I kept inner... Continue Reading
If you're one of the gazillion people who have read The
Hunger Games, then
you’re quite familiar with “Real or Not Real?” And if you
haven't read it, I'm guessing you've at least
heard about this best-selling trilogy.
The Hunger Games movie, like the book, has
been a huge success, grossing over $400 million domestically.
I recently saw an ad for the DVD to be released on August 18
and it got me... Continue Reading
I couldn’t wait to get to the Guinness brewery after landing in
Dublin. Yes, I was eager to taste a pint nearly fresh off
the line, but I was also curious to see if there would be
any indication that the brewery was home to arguably one
of THE most important developments in the field of statistics. I
was not disappointed.
There on the wall in the old Guinness Storehouse was a lone
plaque paying... Continue Reading
last post, I talked about the danger of excluding
interactions between factors in ANOVA and DOE models.
Let’s now look at what can happen if you exclude an important
Warning: misleading high p-value
Minitab regularly hosts webinarson different statistical topics. Let’s suppose we want to
evaluate if certain webinar topics are more popular than others, so
we... Continue Reading
Do you prefer ketchup or soy sauce?
If someone asked you this question, your answer would likely
depend upon what you were eating. You probably wouldn't dunk your
spicy tuna roll in ketchup. And most people (pregnant
moms-to-be excluded) don't seem to fancy eating soy sauce
with hot French fries.
A Common Error When Using ANOVA or DOE to Assess Factors
Modeling techniques such as ANOVA or Design of... Continue Reading
We always hear about the "average" of this and the "average" of
that…the average temperature, the average price of gasoline, the
average number of children per household, etc. In fact, I
just saw an article on average student math scores by country.
If you're a college grad, take a minute to recall when you were
choosing your major. For those of us with aspirations of
making big bucks, studying to... Continue Reading
the field of statistics. It gives us the ability to
remove human bias and opinion to discern between
what is truly important - and significant - from those things
that are not.
For instance, have you ever been at a meeting where a time
series plot is displayed up on the screen and someone declares
there is a spike in the data? Well, according to what? Let's use
the power of statistics and... Continue Reading
Variation is everywhere. It’s in your daily commute to work,
it’s in the amount of caffeine you drink every day, in the number
of e-mails that arrive in your inbox, etc. Whether you’re
monitoring something as ordinary as caffeine consumption or
something more important like a multi-million dollar
manufacturing process, you can use one simple tool to monitor
variation and determine whether the... Continue Reading
Happy Groundhog Day!
For those of you who are not familiar with this crazy American
holiday (or have yet to see the Bill Murray movie by the same
name), every year on February 2nd thousands of excited
onlookers gather in a small Pennsylvania town named Punxsutawney to
find out if spring will come early or if we’ll have to wait another
dreaded 6 weeks for winter to end.And how do we learn what the... Continue Reading
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