True or false: When comparing a parameter for two sets of
measurements, you should always use a hypothesis test to determine
whether the difference is statistically significant.
The answer? (drumroll...) True!
To understand this paradoxical answer, you need to keep in mind
the difference between samples, populations, and descriptive and
Descriptive Statistics and... Continue Reading
mining uses algorithms to explore correlations in data sets. An
automated procedure sorts through large numbers of variables and
includes them in the model based on statistical significance alone.
No thought is given to whether the variables and the signs and
magnitudes of their coefficients make theoretical sense.
We tend to think of data mining in the context of big data, with
its huge... Continue Reading
September 16, is World Ozone Day. You don't hear much about the
ozone layer any more.
In fact, if you’re under 30, you might think this is just
another trivial, obscure observance, along the lines of International Dot Day (yesterday) or National Apple Dumpling Day (tomorrow).
But there’s a good reason that, almost 30 years ago, the United
Nations designated today to as a day to raise... Continue Reading
I confess: I'm not a natural-born decision-maker. Some people—my
wife, for example—can assess even very complex situations, consider
the options, and confidently choose a way forward. Me? I get
anxious about deciding what to eat for lunch. So you can imagine
what it used to be like when I
needed to confront a really big decision or problem. My approach,
to paraphrase the Byrds, was "Re:... Continue Reading
other day I was talking with a friend about control charts, and I
wanted to share an example one of my colleagues wrote on the
Minitab Blog. Looking back through the index for "control
charts" reminded me just how much material we've published on this
Whether you're just getting started with control charts, or
you're an old hand at statistical process control, you'll find some
valuable... Continue Reading
To assess if a process is stable and in statistical control, you
can use a control
chart. It lets you answer the question "is the process that you
see today going to be similar to the process that you see
tomorrow?" To assess and quantify how well your process falls
within specification limits, you can use capability
Both of these tools are easy to use in Minitab, but you
first need to... Continue Reading
performed multiple linear regression and have settled on a model
which contains several predictor variables that are statistically
significant. At this point, it’s common to ask, “Which variable is
This question is more complicated than it first appears. For one
thing, how you define “most important” often depends on your
subject area and goals. For another, how you collect... Continue Reading
There may be huge potential benefits waiting in the data in your
servers. These data may be used for many different purposes. Better
data allows better decisions, of course. Banks, insurance firms,
and telecom companies already own a large amount of data about
their customers. These resources are useful for building a more
personal relationship with each customer.
Some organizations already use... Continue Reading
The college football season is here, and this raises a very
Is Alabama going to be undefeated when they win the national
championship, or will they lose a regular-season game along the
Okay, so it's not a given that Alabama is going to win
the championship this year, but when you've won 4 of the last 7
you're definitely the odds-on favorite.
However, what if we wanted to take... Continue Reading
If you’re in the market for statistical software, there are many
considerations and more than a few options for you to evaluate.
Check out these seven questions to ask yourself before choosing
statistical software—your answers should help guide you towards the
best solution for your needs!
1. Who uses statistical software in your organization?
Are they expert statisticians, novices, or a mix of both?... Continue Reading
In 2011 we had solar panels fitted on our property. In the last
few months we have noticed a few problems with the inverter (the
equipment that converts the electricity generated by the panels
from DC to AC, and manages the transfer of unused electric to the
power company). It was shutting down at various times throughout
the day, typically when it was very sunny, resulting in no
electricity being... Continue Reading
In regression, "sums of squares" are used to represent
variation. In this post, we’ll use some sample data to walk through
sample data used in this post is available within Minitab by
choosing Help > Sample Data,
or File > Open Worksheet >
Look in Minitab Sample Data folder (depending on
your version of Minitab). The dataset is called
ResearcherSalary.MTW, and contains data... Continue Reading
So the data you nurtured, that you worked so hard to format and
make useful, failed the normality test.
Time to face the truth: despite your best efforts, that data set
is never going to measure up to the assumption you may
have been trained to fervently look for.
Your data's lack of normality seems to make it poorly suited for
analysis. Now what?
Take it easy. Don't get uptight. Just let your data... Continue Reading
See if this
sounds fair to you. I flip a coin.
Heads: You win
$1.Tails: You pay me $1.
You may not like games of chance, but you have to admit it seems
like a fair game. At least, assuming the coin is a normal, balanced
coin, and assuming I’m not a sleight-of-hand magician who can
control the coin.
How about this next
You pay me $2 to play.I flip a coin over and over until
it comes up heads.Your... Continue Reading
The Centers for Medicare and Medicaid Services (CMS) updated
their star ratings on July 27. Turns out, the list of hospitals
provide a great way to look at how easy it is to get random samples
from data within Minitab.
Say for example, that you wanted to look at the association
between the government’s new star ratings and the safety rating
scores provided by hospitalsafetyscore.org. The CMS score... Continue Reading
when I used to work in Minitab Tech Support, customers often asked
me, “What’s the difference between Cpk and Ppk?” It’s a good
question, especially since many practitioners default to using Cpk
while overlooking Ppk altogether. It’s like the '80s pop
duo Wham!, where Cpk is George Michael and Ppk is that other
Poofy hairdos styled with mousse, shoulder pads, and leg warmers
aside, let’s... Continue Reading
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
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,
Pennsylvania, with subsidiaries in the United Kingdom, France, and
Australia. Our global network of representatives serves more than 40
countries around the world.