Content by Donald J. Wheeler
Myths About Process Behavior Charts How to avoid some common obstacles to good practice
Wed, 09/07/2011 - 10:56
The simplicity of the process behavior chart can be deceptive. This is because the simplicity of the charts is based on a completely different concept of data analysis than that which is used for the analysis of experimental data. When someone does… Problems With Skewness and Kurtosis,
Part 2What do the shape statistics do?
Mon, 08/01/2011 - 16:11
In part one we found that the skewness and kurtosis parameters characterize the tails of a probability model rather than the central portion, and that because of this, probability models with the same shape parameters will only be similar in overall… 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… 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… 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…
