Content by Donald J. Wheeler

Donald J. Wheeler's picture
Donald J. Wheeler
Inspection sounds simple. Screen out the bad stuff and ship the good stuff. However, measurement error will always create problems of misclassification where good stuff is rejected, and bad stuff...
Donald J. Wheeler's picture
Donald J. Wheeler
In part one we found the baseline portion of an XmR chart to be the best technique for identifying potential outliers among four tests with variable overall alpha levels. In this part we will look at...
Donald J. Wheeler's picture
Donald J. Wheeler
The first statistical test was a test for outliers. The problem of what to do about outliers has been around from the beginnings of data analysis. Part one will compare four tests for outliers. Next...
Donald J. Wheeler's picture
Donald J. Wheeler
Every introductory class in statistics teaches how to obtain a global standard deviation statistic. While this descriptive statistic characterizes the dispersion of the data, it is not the correct...
Donald J. Wheeler's picture
Donald J. Wheeler
On Sept. 29, 2020, the recorded worldwide death toll from Covid-19 reached 1 million. Six days earlier the United States reached 200,000 Covid-related deaths. So how did the United States with only 4...
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Donald J. Wheeler
This article tracks the progression of Covid-19 over the past six months on a state-by-state basis and provides a framework for interpreting these curves by including curves for seven other countries...
Donald J. Wheeler's picture
Donald J. Wheeler
In past articles I have used graphs to provide perspective on how the Covid-19 pandemic is progressing around the world. In this article I shall update some of those graphs and use these historical...
Donald J. Wheeler's picture
Donald J. Wheeler
Since the start of the Covid pandemic I have received many questions about how to analyze the Covid numbers using process behavior charts. Various schemes have been proposed and used. This column...
Donald J. Wheeler's picture
Donald J. Wheeler
With data that come along one number at a time, it is easy to get lost in the details. To see the big picture, it helps to use a time-series graph that will draw your eye in the direction that your...
Donald J. Wheeler's picture
Donald J. Wheeler
In May 2019, James Beagle and I published an article that contained tables for the analysis of mean moving ranges or ANOMmR (pronounced a-nom-m-r). By request of those using this technique, I...