People can make mistakes when they test a hypothesis with
statistical analysis. Specifically, they can make either Type I or
Type II errors.
As you analyze your own data and test hypotheses, understanding
the difference between Type I and Type II errors is extremely
important, because there's a risk of making each type of error in
every analysis, and the amount of risk is in your
if... 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
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
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
People frequently have different opinions. Usually that's
fine—if everybody thought the same way, life would be pretty
boring—but many business decisions are based on opinion. And when
different people in an organization reach different conclusions
about the same business situation, problems follow.
Inconsistency and poor quality result when people being asked to
make yes / no, pass / fail, and... Continue Reading
Did you ever get a pair of jeans or a shirt that you liked, but
didn't quite fit you perfectly? That happened to me a few months
ago. The jeans looked good, and they were very well made, but it
took a while before I was comfortable wearing them.
I much prefer it when I can get a pair with a perfect fit, that
feel like I was born in them, with no period of
So which pair do you think I... Continue Reading
The language of statistics is a funny thing, but there usually
isn't much to laugh at in the consequences that can follow when
misunderstandings occur between statisticians and
non-statisticians. We see these consequences frequently in the
media, when new studies—that usually contradict previous ones—are
breathlessly related, as if their findings were incontrovertible
Similar, though less... Continue Reading
The line plot is an incredibly
agile but frequently overlooked tool in the quest to better
understand your processes.
In any process, whether it's baking a cake or processing loan
forms, many factors have the potential to affect the outcome.
Changing the source of raw
materials could affect the strength of plywood a factory produces.
Similarly, one method of gluing this plywood might be better... Continue Reading
A member of Minitab's LinkedIn
group asked how to create a chart to monitor change by
month, specifically comparing last year's data to this year's data.
My last post showed how to do this using an
Individuals Chart of the differences between this year's and
last year's data. Here's another approach suggested by a
participant in the group.
Applying Statistical Thinking
An individuals chart of the... Continue Reading
LinkedIn group is a good place to ask questions and get
input from people with experience analyzing data and doing
statistics in a wide array of professions. For example, one member
asked this question:
I am trying to create a chart
that can monitor change by month. I have [last year's] data and
want to compare it to [this year's] data...what chart should I use,
and can I auto-update it?... Continue Reading
Pareto charts are a special type of bar chart you can use to
prioritize almost anything. This makes them very useful in making
sound decisions. For example, if you have several possible quality
improvement projects, but not enough time or people to do them all
now, you can use a Pareto chart to identify which projects have the
most potential for making meaningful improvement.
Pareto charts look... Continue Reading
If your work involves quality improvement, you've at least
heard of Design of Experiments (DOE). You probably know
it's the most efficient way to optimize and improve your process.
But many of us find DOE intimidating, especially if it's not a tool
we use often. How do you select an appropriate design, and ensure
you've got the right number of factors and levels? And after you've
gathered your... Continue Reading
Every day, thousands of people withdraw extra cash for daily
expenses. Each transaction may be small, but the total amount of
cash dispersed over hundreds or thousands of daily transactions can
be very high. But every bank branch has a fixed cash flow, which
must be set without knowing what each customer will need on a given
day. This creates a challenge for financial entities. Customers
expect... Continue Reading
A reader asked a great
question in response to a post I wrote
about Pareto charts. Our readers typically do ask great questions,
but this one turned out to be more difficult to answer than it
My correspondent wrote:
My understanding is that when you have count data, a
bar chart is the way to go. The gaps between the bars emphasize
that the data are not measured on a continuous scale.... Continue Reading
We hosted our first-ever Minitab Insights conference in
September, and if you were among the attendees, you already know
the caliber of the speakers and the value of the information they
shared. Experts from a wide range of industries offered a lot of
great lessons about how they use data analysis to improve business
practices and solve a variety of problems.
I blogged earlier about five key...Continue Reading
watched an old motorcycle flick from the 1960s the other night, and I
was struck by the bikers' slang. They had a language all their own.
Just like statisticians, whose manner of speaking often confounds
those who aren't hep to the lingo of data analysis.
It got me thinking...what if there were an all-statistician
biker gang? Call them the Nulls Angels. Imagine them in their
colors, tearing... Continue Reading
If you were among the 300 people who attended the first-ever
Minitab Insights conference in September, you already know how
powerful it was. Attendees learned how practitioners from a
wide range of industries use data analysis to address a variety of
problems, find solutions, and improve business practices.
In the coming weeks and months, we will share more of the great
insights and guidance shared... 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.