In my last post, I wrote about
making a cluttered data set easier to work with by removing
unneeded columns entirely, and by displaying just those columns you
want to work with now. But
too much unneeded data isn't always the problem.
What can you do when someone
gives you data that isn't organized the way you need it to be?
That happens for a variety of
reasons, but most often it's because the... Continue Reading
Isn't it great when you get a set of data and it's perfectly
organized and ready for you to analyze? I love it when the people
who collect the data take special care to make sure to format it
consistently, arrange it correctly, and eliminate the junk,
clutter, and useless information I don't need.
never received a data set in such perfect condition, you say?
Yeah, me neither. But I can... Continue Reading
can be a tricky thing. Consider trying to predict the number rolled
by 2 six-sided dice. We know that 7 is the most likely outcome. We
know the exact probability each number has of being rolled. If we
rolled the dice 100 times, we could calculate the expected value
for the number of times each value would be rolled. However, even
with all that information, we can't definitively predict... Continue Reading
In its industry guidance to companies that manufacture drugs and
biological products for people and animals,
the Food and Drug Administration (FDA) recommends three stages for
Process Qualification, and Continued Process Verification. In
this post, we we will focus on that third stage.
Stage 3: Continued Process Verification
Per the FDA guidelines, the goal of... Continue Reading
Welcome to the Hypothesis Test Casino! The featured game of the
house is roulette. But this is no ordinary game of
roulette. This is p-value roulette!
Here’s how it works: We have two roulette wheels, the Null wheel
and the Alternative wheel. Each wheel has 20 slots (instead of the
usual 37 or 38). You get to bet on one slot.
What happens if the ball lands in the slot you bet on? Well,
that depends... Continue Reading
many, my introduction to 17th-century French philosophy came at the
tender age of 3+. For that is when I discovered the
Etch-a-Sketch®, an entertaining ode to Descartes' coordinate plane.
Little did I know that the seemingly idle hours I spent doodling
on my Etch-a-Sketch would prove to be excellent training for the
feat that I attempt today: plotting an Empirical Cumulative
Distribution... 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
To make objective
decisions about the processes that are critical to your
organization, you often need to examine categorical data. You may
know how to use a t-test or ANOVA when you’re comparing measurement
data (like weight, length, revenue, and so on), but do you know how to compare
attribute or counts data? It easy to do with statistical software
One person may look at
this bar... Continue Reading
by Matthew Barsalou, guest
The old saying “if it walks like a duck, quacks like a duck and
looks like a duck, then it must be a duck” may be appropriate in
bird watching; however, the same idea can’t be applied when
observing a statistical distribution. The dedicated ornithologist
is often armed with binoculars and a field guide to the local birds
and this should be sufficient. A... 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
Genichi Taguchi is famous for his pioneering methods of robust
quality engineering. One of the major contributions that he made to
quality improvement methods is Taguchi designs.
Designed experiments were first used by agronomists during
the last century. This method seemed highly theoretical at first,
and was initially restricted to agronomy. Taguchi made the designed
experiment approach more... Continue Reading
In its industry guidance to companies that manufacture drugs and
biological products for people and animals, the Food and Drug
Administration (FDA) recommends three stages for process
my last post covered
statistical tools for the Process Design stage, here we will
focus on the statistical techniques typically utilized for the
second stage, Process Qualification.
Stage 2: Process... Continue Reading
T'was the season for toys recently, and Christmas day found me
playing around with a classic, the Etch-a-Sketch. As I noodled with
the knobs, I had a sudden flash of recognition: my drawing reminded
me of the Empirical CDF Plot in Minitab Statistical Software. Did you just ask,
"What's a CDF plot? And what's so empirical about it?" Both very
good questions. Let's start with the first, and we'll... Continue Reading
In my last post on
DMAIC tools for the Define phase, we reviewed various graphs
and stats typically used to define project goals and
customer deliverables. Let’s now move along to the tools you can
use in Minitab
Statistical Software to conduct the Measure phase.
Measure Phase Methodology
The goal of this phase is to measure the process to
determine its current performance and quantify the problem.... 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
Process validation is vital to the success of companies that
manufacture drugs and biological products for people and animals.
According to the FDA guidelines published by the U.S. Department of
Health and Human Services:
“Process validation is defined as
the collection and evaluation of data, from the process design
state through commercial production, which establishes scientific
evidence that a... Continue Reading
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