Content by Donald J. Wheeler
Problems with Skewness and Kurtosis,
Part OneWhat do the shape parameters do?
Fri, 07/29/2011 - 16:30
With the use of statistical software, many individuals are being exposed to more than just measures of location and dispersion. In addition to the average and standard deviation, they often find some funny numbers labeled as skewness and kurtosis.… Problems With Risk Priority NumbersAvoiding more numerical jabberwocky
Mon, 06/27/2011 - 13:18
Failure mode and effects analysis (FMEA) is an engineering tool that has been heavily adapted for use in Six Sigma programs where it is commonly used to decide which problem to work on. In this usage a risk priority number (RPN) is computed for each… Estimating the Fraction Nonconforming How to know what the data are really telling you
Tue, 05/31/2011 - 12:03
Whenever we present capability indexes the almost inevitable follow-up question is, “What is the fraction nonconforming?” What this question usually means is, “Tell me what these capability indexes mean in terms that I can understand.” These… 100% Inspection and Measurement ErrorHow to handle the problem of misclassified product
Tue, 05/03/2011 - 09:50
One-hundred-percent inspection is commonly used to avoid shipping nonconforming product. Each of the items produced is measured and judged to be either conforming or nonconforming. The conforming items get shipped, and the nonconforming items get… How Measurement Error Affects the Four Ways We Use DataUnderstanding probable error and the intraclass correlation coefficient makes it possible to quantify measurement uncertainty
Mon, 04/04/2011 - 05:30
Measurement error is generally considered to be a bad thing, and yet there is very little written about how measurement error affects the way we use our measurements.
This column will consider these effects for four different uses of data. But first… How Measurement Error Affects the Four Ways We Use DataUnderstanding Probable Error and the Intraclass Correlation Coefficient makes it possible to quantify measurement uncertainty
Mon, 04/04/2011 - 05:30
Measurement error is generally considered to be a bad thing, and yet there is very little written about how measurement error affects the way we use our measurements.
This column will consider these effects for four different uses of data. But… Three Questions for SuccessThe necessity of using operational definitions
Tue, 03/01/2011 - 04:30
All improvement efforts require a framework. No matter what we are doing, we all need some way to align our efforts and focus on a specific objective. During my 40 years in this business, I have seen many different models offered as frameworks for… A Better Way to Do R&R StudiesEvaluating the measurement process approach
Tue, 02/01/2011 - 07:04
Last month’s column looked at how to fix some of the Problems with Gauge R&R Studies. This month I will show you how to learn more from your gauge repeatability and reproducibility (R&R) data with less effort. Rather than getting lost in a… Problems With Gauge R&R StudiesHow to make sense of your repeatability and reproducibility (R&R) values
Mon, 01/03/2011 - 04:30
Measurement error is ubiquitous. As a result, over the past 250 years, different areas of science and engineering have come up with many different ways to deal with the problem. One approach to the problem of measurement error was developed during… The Intraclass Correlation CoefficientIs your measurement system adequate?
Thu, 12/02/2010 - 15:26
In my July column, “Where Do Manufacturing Specifications Come From?” we found that the intraclass correlation coefficient is the natural measure of relative utility. This measure is theoretically sound and easy to explain. This column will look at…
