Communicating statistical concepts quickly and clearly is just as critical as being able to calculate them, so I focus on quick, practical insights about statistics to help you make data-driven decisions. Continue Reading »
famous classical Chinese poem from the Song dynasty describes the
views of a mist-covered mountain called Lushan.
The poem was inscribed on the wall of a Buddhist monastery by
Su Shi, a renowned poet, artist, and
calligrapher of the 11th century.
Deceptively simple, the poem captures the illusory nature of
Written on the Wall of West Forest Temple
... Continue Reading
previous post examined how an equivalence test
can shift the burden of proof when you perform hypothesis test of
the means. This allows you to more rigorously test whether the
process mean is equivalent to a target or to another mean.
Here’s another key difference: To perform the analysis, an
equivalence test requires that you first define, upfront, the size
of a practically important difference... Continue Reading
more options, come more decisions.
With equivalence testing added to Minitab 17, you now have more
statistical tools to test a sample mean against target value or
another sample mean.
Equivalence testing is extensively used in the biomedical field.
Pharmaceutical manufacturers often need to test whether the
biological activity of a generic drug is equivalent to that of a
brand name drug that... Continue Reading
n' begorrah, it's St. Patrick's Day today!
The day that we Americans lay claim to our Irish heritage by
doing all sorts of things that Irish people never do. Like dye your
hair green. Or tell everyone what percentage Irish you are.
Despite my given name, I'm only about 15% Irish. So my Irish
portion weighs about 25 pounds. It could be the portion that hangs
over my belt due to excess potatoes... Continue Reading
By popular demand, Release 17 of Minitab
Statistical Software comes with a new graphical analysis called
the Bubble Plot.
This exploratory tool is great for visualizing the relationships
among three variables on a single plot.
To see how it works, consider the total medal count by country
from the recently completed 2014 Olympic Winter Games. Suppose I
want to explore whether there might be a... Continue Reading
you regularly perform regression analysis, you know that
R2 is a statistic used to evaluate the fit of your
model. You may even know the standard definition of R2:
the percentage of variation in the response that is explained
by the model.
Fair enough. With Minitab Statistical Software doing all the heavy
lifting to calculate your R2 values, that may be all you
ever need to know.
But if you’re... Continue Reading
This close to
the holidays, it’s hard to stay focused on work.
I should be writing a post about useful estimation
tools for quality statistics. But all those yuletide carols about
hosts of angels singing from on high have distracted me.
Alas, I’ve fallen into the clutches of one of the world’s oldest
estimation problems, posed centuries ago by medieval scholars:
Just how many heavenly angels can... Continue Reading
factors significantly affect how quickly my couch-potato pooch
obeys the “Lay Down” command?
The cushiness of the floor surface? The tone of voice used? The
type of reward she gets? How hungry she is?
I created a 1/8 fraction Resolution IV design
for 7 factors and collected response data for 16 runs. Now it’s
time to analyze the data in Minitab, using Stat
> DOE > Factorial > Analyze Factorial... Continue Reading
Nala, our 6-year-old
golden retriever, loves her dogma. That's her sitting
in front of church on Sunday morning.
But she's not crazy about her catechism. For example, she
doesn't always dutifully follow the "Lay Down" commandment.
What factors may be influencing her response? We're
performing a DOE screening experiment to find out.
In this post, we'll use Minitab
Statistical Software to
Create the... Continue Reading
of experiments (DOE) is an extremely practical and cost-effective
way to study the effects of different factors and their
interactions on a response.
But finding your way through DOE-land can be daunting when
you're just getting started. So I've enlisted the support of a
friendly golden retriever as a guide dog to walk us through a
simple DOE screening experiment.
Nala, the golden retriever,... Continue Reading
What do you see
when you look at the image at right?
Do you see a bulging sphere that stretches the checkerboard
pattern in the center, causing its lines to curve?
Are you sure? Look again. This time, test any “curved” line by
holding a straightedge next to it.
The image is actually composed of small squares and straight
lines. Yet, when perceived as a composite whole, it creates a
completely... Continue Reading
the prospect of a looming U.S. government shutdown depress you?
Are you tired of the ongoing game of Chicken played over our
federal budget? The dissonant hysterics of deficit drama
queens? The glib arrogance of deficit deniers?
Then it might be a good time to take a break and focus on
something more pleasant. Something you can control. Something you
can improve and make more beautiful.
Like... Continue Reading
can cause a lot of pain to your customer.
They can also cause a lot of pain inside your body. The picture
at right shows my broken right clavicle. Ouch!
You might think of it as the defective output
from my bicycling process, which needs improvement.
Sitting around all summer cinched up in a foam orthopedic
brace hasn’t exactly been wild and wacky 50s-style fun at the
But the injury has... Continue Reading
wildfire season out West. Time to be in awe of the destructive
power of Nature.
According to active fire maps by the USDA Forest
Service, over 300 fires are now burning across a total of 1.5
million acres—including 35 large, uncontained blazes.
Shifting winds, humidity, and terrain can quickly alter a fire's
intensity. In extreme conditions, flames can reach over 150 feet,
with temperatures...Continue Reading
confession: Nothing fires quickly from the top of my head. At least
nothing very lucid or useful.
To come up with a good idea, I have to dredge thoughts slowly
from the thick sludge and sediment in my brain.
It's not always easy—there are deeply
encrusted layers in my cerebral cortex that go all
the way back to the Paleozoic era.
So coming up with a useful data display—one that
uncovers hidden... Continue Reading
Uncle Joe is always fantasizing about ways to outsmart Father
“Suppose you could reverse your aging process at some fixed
point in your life,” he says to me, a crazed gleam in his
“So you could pick any age to turn the clock backwards and start
aging in reverse. What age would you pick to try to maximize your
In other words, suppose you pick age 75. That means you’d... Continue Reading
Republican or Democrat.
Yin or yang.
Why is it that life often seems to boil down to two choices?
Heck, it even happens when you open the Basic
Stats menu in Minitab. You’ll see a choice between a
2-sample t-test and a paired t-test:
Which test should you choose? And what’s at stake?
Ask a statistician, and you might get this response:
"Elementary, my dear Watson. Choose the 2-sample... Continue Reading
t-test is one of the most frequently used procedures in
But even people who frequently use t-tests often don’t know
exactly what happens when their data are wheeled away and operated
upon behind the curtain using statistical software
It’s worth taking a quick peek behind that curtain.
Because if you know how a t-test works, you can understand what
your results really mean.... Continue Reading
you’re 3 years old, you probably can’t have things just the
way you want them all the time.
You can’t always have peanut butter and ranch dressing
on your toast. Or ketchup on your pineapple. Or sugar sprinkles on
But there is one small arena in life over which you can still
exert your control.
Tools > Options in Minitab's statistical softwareallows you to change selected default... Continue Reading
“Shall I compare thee to a standard normal distribution?
Thou art more symmetric and more bell-shaped…”
— Melvin Shakespeare (William’s lesser-known statistician
The Greek philosopher Aristotle believed that symmetry was one
of the primary elements of the universal ideal of beauty. Over 2000
years later, emerging research seems to bear him out.
Studies suggest we tend to be more... 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.
Minitab Inc. is a privately owned company headquartered in State College,
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countries around the world.