Statistics Features

Donald J. Wheeler's picture
Donald J. Wheeler
Lean production is built on the explicit assumption that each step is operated predictably and capably. Predictable operation can only be achieved and maintained by using process behavior charts...
Harish Jose's picture
Harish Jose
It has been a while since I have written about statistics, and I get asked a lot about a way to calculate sample sizes based on reliability and confidence levels. So today I am sharing a spreadsheet...
Donald J. Wheeler's picture
Donald J. Wheeler
In the past two months we have looked at how three-sigma limits work with skewed data. This column finds the power functions for the probability limits of phase two charts with skewed probability...
Jody Muelaner's picture
Jody Muelaner
One of the key ideas in lean manufacturing is that defects should be detected as early as possible. Efforts to control manufacturing processes, so that issues can be detected before defects...
Bill Snyder's picture
Bill Snyder
In 1500, China’s economy was the strongest in the world. But by the 19th century, the United States, Western Europe, and Japan had leapfrogged over China by churning out goods and services in vast...
Anthony D. Burns's picture
Anthony D. Burns
You’ve set aside Sunday afternoon to bake some cookies, but you discover you have run out of eggs. Your partner in marital bliss has gone out and taken the car. You call a couple of mates, and they...
Christopher Shoe's picture
Christopher Shoe
According to a recent LNS Research survey, 37 percent of quality leaders cite an inability to measure quality metrics as their No. 1 barrier to achieving quality goals. Even worse, the survey...
Donald J. Wheeler's picture
Donald J. Wheeler
Last month I looked at how the fixed-width limits of a process behavior chart filter out virtually all of the routine variation regardless of the shape of the histogram. In this column I will look at...
Yen Duong's picture
Yen Duong
If you think it’s hard to tell how you’re doing at your job, imagine being a hockey goalie. Let’s say you block every shot in a game. Was that performance due to your superior skills? Or maybe just...
Donald J. Wheeler's picture
Donald J. Wheeler
The oldest myth about process behavior charts is the myth that they require “normally distributed data.” If you have ever heard this idea, or if you have ever taught this to others, then you need to...
Steve Moore's picture
Steve Moore
Pickleball is arguably the fastest-growing sport in the United States, especially among baby-boomer retirees. This game is similar to tennis, but is played on a smaller court (44 ft × 20 ft) with a...
Davis Balestracci's picture
Davis Balestracci
As statistical methods become more embedded in everyday organizational quality improvement efforts, I find that a key concept is often woefully misunderstood, if it is even taught at all. W. Edwards...
Jody Muelaner's picture
Jody Muelaner
In a general sense, capability is the ability to do something. Within manufacturing, capability is given a much more specific definition. It is an expression of the accuracy of a process or equipment...
Donald J. Wheeler's picture
Donald J. Wheeler
Recently I have had several questions about which bias correction factors to use when working with industrial data. Some books use one formula, other books use another, and the software may use a...
Rohit Mathur's picture
Rohit Mathur
Whatever the process or type of data collected, all data display variation. This is also true in software development. Any measure or parameter of interest to our business will vary from time period...
Donald J. Wheeler's picture
Donald J. Wheeler
During the past three months James Beagle and I presented columns that made extensive use of analysis of means techniques. Since these techniques may be new to some, this column explains when to use...
Romesh Saigal's picture
Romesh Saigal
Soon after the Great Recession, the U.S. stock markets plunged—and rebounded within 36 minutes. The Dow Jones Industrial Average dropped more than 9 percent, losing more than 1,000 points before...
Scott A. Hindle's picture
Scott A. Hindle
In everyday language, “in control” and “under control” are synonymous with “in specification.” Requirements have been met. Things are OK. No trouble. “Out of control,” on the other hand, is...
Chad Kymal's picture
Chad Kymal
During the early 1980s, GM, Ford, and Chrysler established the Automotive Industry Action Group (AIAG), a not-for-profit organization with the mission “To improve its members’ competitiveness through...
Davis Balestracci's picture
Davis Balestracci
Recently, I’ve had a sad, increasing sense of déjà vu. Twitter has become even more vacuous, and LinkedIn has quickly devolved into a business version of Facebook. Literally right after I...