Statistics Features

Anthony Chirico's picture
Anthony Chirico
In my first article, the merits and cautions of AS9138 c=0 sampling plans were discussed and a simple formula was provided to determine the required sample size to detect nonconforming units. In the...
Anthony Chirico's picture
Anthony Chirico
In my previous article, I discussed the merits and cautions of the “acceptance number” equal zero (c=0) sampling plans contained within AS9138. A simple formula was provided to determine appropriate...
Anthony Chirico's picture
Anthony Chirico
Aerospace standard AS9138—“Quality management systems statistical product acceptance requirements” was issued this year (2018), a few years after its accompanying guidance materials in section 3.7 of...
Dirk Dusharme @ Quality Digest's picture
Dirk Dusharme @ Quality Digest
In this all-manufacturing episode, we look at the STEM pipeline into manufacturing, supplier development, how to make sense of manufacturing data and, no, manufacturing is not dead. “Strengthening...
Donald J. Wheeler's picture
Donald J. Wheeler
Parts one and two of this series illustrated four problems with using a model-building approach when data snooping. This column will present an alternative approach for data snooping that is of...
Davis Balestracci's picture
Davis Balestracci
During the early 1990s, I was president of the Twin Cities Deming Forum. I had a wonderful board whose members were full of great ideas. One member, Doug Augustine, was a 71-year-old retired Lutheran...
Laurel Thoennes @ Quality Digest's picture
Laurel Thoennes @ Quality Digest
In the foreword of Mark Graban’s book, Measures of Success: React Less, Lead Better, Improve More (Constancy Inc., 2018), renowned statistician, Donald J. Wheeler, writes about Graban: “He has...
Rip Stauffer's picture
Rip Stauffer
I must admit, right up front, that this is not a totally unbiased review. I first became aware of Davis Balestracci in 1998, when I received the American Society for Quality (ASQ) Statistics Division...
Donald J. Wheeler's picture
Donald J. Wheeler
In “Data Snooping Part 1” (Quality Digest, Aug. 6, 2018) we discovered the basis for the first caveat of data snooping. Here we discover three additional caveats of data snooping. Last month we...
Donald J. Wheeler's picture
Donald J. Wheeler
Data mining is the foundation for the current fad of “big data.” Today’s software makes it possible to look for all kinds of relationships among the variables contained in a database. But owning a...
William A. Levinson's picture
William A. Levinson
Quality and manufacturing practitioners are most familiar with the effect of variation on product quality, and this is still the focus of the quality management and Six Sigma bodies of knowledge....
Donald J. Wheeler's picture
Donald J. Wheeler
The ultimate purpose for collecting data is to take action. In some cases the action taken will depend upon a description of what is at hand. In others the action taken will depend upon a prediction...
Douglas C. Fair's picture
Douglas C. Fair
A few months back, I was reading a really good article from The Wall Street Journal, titled “Stop Using Excel, Finance Chiefs Tell Staffs.” Even though it was geared toward accounting and...
NACS's picture
NACS
The phrase, “Are we there yet?” has long been associated with boring summer road trips. However, a new study shatters that myth, as it shows that 69 percent of people say traveling to their...
Harish Jose's picture
Harish Jose
I have written about sample size calculations many times before. One of the most common questions a statistician is asked is, “How many samples do I need—is a sample size of 30 appropriate?” The...
Scott A. Hindle's picture
Scott A. Hindle
I recently got hold of the set of data shown in figure 1. What can be done to analyze and make sense of these 65 data values is the theme of this article. Read on to see what is exceptional about...
Scott Weaver's picture
Scott Weaver
The Atlantic hurricane season is now upon us, and the National Oceanic and Atmospheric Administration (NOAA) has just released its 2018 seasonal hurricane outlook which calls for a slightly above...
Anthony D. Burns's picture
Anthony D. Burns
Quality is related to processes. A process is “a series of actions or steps taken in order to achieve a particular end.” It doesn’t matter whether the process is the handling of invoices, customers...
Cheryl Pammer's picture
Cheryl Pammer
Confidence intervals show the range of values we can be fairly, well, confident, that our true value lies in, and they are very important to any quality practitioner. I could be 95-percent confident...
Rip Stauffer's picture
Rip Stauffer
A lot of people in my classes struggle with conditional probability. Don’t feel alone, though. A lot of people get this (and simple probability, for that matter) wrong. If you read Innumeracy by John...