Statistics Features

Dan Nelson's picture
Dan Nelson
Have you ever noticed someone struggling with a problem because he didn’t know the “trick” to solving it? Have you ever wrestled with a problem, only to discover that it actually wasn’t a...
Arun Hariharan's picture
Arun Hariharan
Technology is a useful tool in quality. That said, there are limits to what technology can do. Here’s my summary of its advantages and disadvantages for quality professionals. 1. Data and...
Donald J. Wheeler's picture
Donald J. Wheeler
The Levey-Jennings chart was created in the 1950s to answer questions about the quality and consistency of measurement systems in the chemical and process industries. This column will illustrate...
Greg Fox's picture
Greg Fox
Unless you live under a rock, you’ve no doubt heard that the world recently lost David Bowie, one of the greatest artists of our time. My memories of the Thin White Duke go all the way back to...
Eston Martz's picture
Eston Martz
Not long ago, I couldn’t abide statistics. I respected the field, in much the same way a gazelle respects a lion. Most of my early experiences with statistics indicated that close encounters...
Donald J. Wheeler's picture
Donald J. Wheeler
One computation that modern software offers to unsuspecting users is the statistical tolerance interval. Since this sounds very much like limits for individual values, some have been tempted to use...
Fred Schenkelberg's picture
Fred Schenkelberg
The planning of environmental or reliability testing becomes a question of sample size at some point. It’s probably the most common question I hear as a reliability engineer: How many samples do we...
Davis Balestracci's picture
Davis Balestracci
“It is impossible to tell how widespread data torturing is. Like other forms of torture, it leaves no incriminating marks when done skillfully. And like other forms of torture, it may be difficult...
William A. Levinson's picture
William A. Levinson
The Shewhart control chart is relatively insensitive to non-normal distributions, and the worst foreseeable consequences of a wrong decision involve searching for an assignable or special cause...
Michelle Paret's picture
Michelle Paret
I have two young children, and I work full-time, so my adult TV time is about as rare as finding a Kardashian-free tabloid. So I can’t commit to just any TV show. It better be a good one. I was...
Davis Balestracci's picture
Davis Balestracci
“When I die, let it be in a meeting. The transition from life to death will be barely perceptible.” —Anonymous Today I’m going to share some ideas from an always-thoughtful newsletter written by...
Douglas C. Fair's picture
Douglas C. Fair
Sponsored Content Statistical process control (SPC) software has been around for decades, used by manufacturers across industries to help monitor process behavior and control quality on the shop...
Eston Martz's picture
Eston Martz
I read trade publications that cover everything from banking to biotech, looking for interesting perspectives on data analysis and statistics, especially where they pertain to quality improvement...
William A. Levinson's picture
William A. Levinson
We all know what happens when we assume. For example, traditional designed experiments assume that residuals, the differences between the actual and modeled data, follow the normal distribution (as...
Jim Colton's picture
Jim Colton
How many samples do you need to be 95-percent confident that at least 95 percent—or even 99 percent—of your product is good? The answer depends on the type of response variable you are using—...
Eston Martz's picture
Eston Martz
Whatever industry you’re in, you’re going to need to buy supplies. If you’re a printer, you’ll need to purchase inks, various types of printing equipment, and paper. If you’re in manufacturing, you...
Scott A. Hindle's picture
Scott A. Hindle
When considering how good a production process is, it’s important to ask, “Can we expect the output to be fully conforming?” An assessment of process capability can answer this. Data are needed,...
Douglas Allen's picture
Douglas Allen
It’s a cold winter’s night in northern New Hampshire. You go out to the woodshed to grab a couple more logs, but as you approach, your hear a rustling inside the shed. You’ve gotten close enough to...
Donald J. Wheeler's picture
Donald J. Wheeler
Story update 9/8/2015: There was an error in the data set for columns "Skew" and "Kurt" in figure 7. The error has been corrected. Clear thinking and simplicity of analysis...
Joel Smith's picture
Joel Smith
Just 100 years ago, very few statistical tools were available and the field was largely unknown. Since then, there has been an explosion in available tools, as well as ever-increasing...