Figures lie, so they say, and liars figure. A recent post at Ben
Orlin's always-amusing mathwithbaddrawings.com blog nicely
encapsulates why so many people feel wary about anything
related to statistics and data analysis. Do take a moment to check it out, it's a fast
all of the scenarios Orlin offers in his post, the statistical
statements are completely accurate, but the person offering... Continue Reading
Often, when we start analyzing
new data, one of the very first things we look at is whether
certain pairs of variables are correlated. Correlation can tell if two variables have a
linear relationship, and the strength of that
makes sense as a starting point, since we're usually looking for
relationships and correlation is an easy way to get a quick handle
on the data set we're... Continue Reading
games are about to begin in Rio de Janeiro. Over the next 16 days,
more than 11,000 athletes from 206 countries will be competing in
306 different events. That's the most events ever in any Olympic
games. It's almost twice as many events as there were 50 years ago,
and exactly three times as many as there were 100 years ago.
Since the number of Olympic events has changed over time,... Continue Reading
My recent beach vacation began with the kind of unfortunate
incident that we all dread: killing a distant relative.
It was about 3 a.m. Me, my two sons, and our dog had been on the
road since about 7 p.m. the previous day to get to our beach house
on Plum Island, Massachusetts. Google maps said our exit was coming
up and that we were only about 15 minutes away from our palace.
Buoyed by that... Continue Reading
Have you ever accidentally done statistics? Not all of us can
(or would want to) be “stat nerds,” but the word “statistics”
shouldn’t be scary. In fact, we all analyze things that happen to
us every day. Sometimes we don’t realize that we are compiling data
and analyzing it, but that’s exactly what we are doing. Yes, there
are advanced statistical concepts that can be difficult to
understand—but... Continue Reading
Statistics is all about modelling. But that doesn’t mean strutting down the
catwalk with a pouty expression.
It means we’re often looking for a mathematical form that best
describes relationships between variables in a population, which we
can then use to estimate or predict data values, based on known
To aid in the search and selection of a “top model,” we often
utilize... Continue Reading
When I blogged about
automation back in March, I made my husband out to be an
automation guru. Well, he certainly is. But what you don’t know
about my husband is that while he loves to automate everything in
his life, sometimes he drops the ball. He’s human; even I have to
cut him a break every now and then.
On the other hand, instances of hypocrisy in his behavior tend
to make for a good story.... Continue Reading
You need to consider many factors when you’re buying a used car.
Once you narrow your choice down to a particular car model, you can
get a wealth of information about individual cars on the market
through the Internet. How do you navigate through it all to find
the best deal? By analyzing the data you have available.
Let's look at how this works using
the Assistant in Minitab 17. With the... Continue Reading
Here is a scenario involving process capability that we’ve seen
from time to time in Minitab's technical support department. I’m
sharing the details in this post so that you’ll know where to look
if you encounter a similar situation.
You need to run a capability analysis. You generate the output
Statistical Software. When you look at the results, the Cpk is
huge and the histogram in... Continue Reading
If you've used our software, you’re probably used to
many of the things you can do in Minitab once you’ve fit a
model. For example, after you fit a response to a given model for
some predictors with Stat > DOE > Response Surface
> Analyze Response Surface Design, you can do the
Predict the mean value of the response variable for new
combinations of settings of the predictors.
Draw... 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
In the great 1971 movie Willy Wonka and the Chocolate
Factory, the reclusive owner of the Wonka Chocolate Factory
decides to place golden tickets in five of his famous chocolate
bars, and allow the winners of each to visit his factory with a
guest. Since restarting production after three years of silence, no
one has come in or gone out of the factory. Needless to say, there
is enormous interest in... Continue Reading
Tuesday Night, Major League Baseball announced the rosters for
tomorrow's All-Star game in
San Diego. Immediately, as I'm sure was anticipated, people
began talking about who made it and who didn't. Who got left out,
and who shouldn't have made it.
As a fun little exercise, I decided to take a visual look at the
all-star teams, to see what kind of players were selected. I looked
at position... Continue Reading
you perform a statistical analysis, you want to make sure you
collect enough data that your results are reliable. But you also
want to avoid wasting time and money collecting more data than you
need. So it's important to find an appropriate middle ground when
determining your sample size.
Now, technically, the Major League Baseball regular season isn't
a statistical analysis. But it does kind... Continue Reading
In my last post, we took the red pill and dove
deep into the unarguably fascinating and uncompromisingly
compelling world of the matrix plot. I've stuffed this post with
information about a topic of marginal interest...the marginal
Margins are important. Back in my English composition days, I
recall that margins were particularly prized for the inverse linear
relationship they maintained with... 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
Since it's summer grilling season, I'm
applying the Assistant's DOE tool to outdoor
cooking. Earlier, I showed
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.
if you're a long-time user of designed experiments, it's still easy
to... Continue Reading
been called a "demographic watershed".
In the next 15 years alone, the worldwide population of
individuals aged 65 and older is projected to increase more
than 60%, from 617 million to about 1 billion.1
Increasingly, countries are asking themselves: How can we
ensure a high quality of care for our growing aging
population while keeping our healthcare costs under control?
The answer? More... Continue Reading
Earlier this month, PLOS.org
published an article titled "Ten Simple Rules for Effective Statistical
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
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