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
again, with the arrival of autumn, it's time for a flu shot.
I get a flu shot every year even though I know they’re not
perfect. I figure they’re a relatively easy and inexpensive way to
reduce the chance of having a miserable week.
I’ve heard on various news media that their effectiveness is
about 60%. But what does 60% effectiveness mean, exactly? How much
does this actually reduce the... Continue Reading
In Part 1 of this
blog series, I wrote about how statistical inference uses data
from a sample of individuals to reach conclusions about the whole
population. That’s a very powerful tool, but you must check your
assumptions when you make statistical inferences. Violating any of
these assumptions can result in false positives or false negatives,
thus invalidating your results.
The common data... Continue Reading
Statistical inference uses data from a sample of individuals to
reach conclusions about the whole population. It’s a very
powerful tool. But as the saying goes, “With great
power comes great responsibility!” When attempting to make
inferences from sample data, you must check your assumptions.
Violating any of these assumptions can result in false positives or
false negatives, thus invalidating... Continue Reading
Data mining can be helpful in the exploratory phase of an
analysis. If you're in the early stages and you're just figuring
out which predictors are potentially correlated with your response
variable, data mining can help you identify candidates. However,
there are problems associated with using data mining to select
In my previous post, we used data mining to settle on
the following... Continue Reading
The ultimate goal of most quality improvement projects is clear:
reducing the number of defects, improving a response, or making a
change that benefits your customers.
We often want to jump right in and start gathering and analyzing
data so we can solve the problems. Checking your measurement
systems first, with methods like attribute agreement analysis or
Gage R&R, may seem like a needless waste... Continue Reading
Face it, you love regression analysis as much as I do.
Regression is one of the most satisfying analyses in Minitab:
get some predictors that should have a relationship to a response,
go through a model selection process, interpret fit statistics like
adjusted R2 and predicted R2, and make
predictions. Yes, regression really is quite wonderful.
Except when it’s not. Dark, seedy corners of the data... Continue Reading
We’ve got a plethora of case studies showing how businesses from different
industries solve problems and implement solutions with data
analysis. Take a look for ideas about how you can use data analysis
to ensure excellence at your business!
Boston Scientific, one of the world’s leading developers of
medical devices, is just one organization who has shared their
story. A team at their Heredia,... Continue Reading
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
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
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
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