Tue, 12/06/2011 - 14:58
Many times measurements are made using measurement increments which are too large for the job. Fortunately this problem is easily detected by ordinary, production-line process behavior charts. No special studies are necessary; no standard parts…
Fri, 10/28/2011 - 09:23
From the perspective of data analysis, rare events are problematic. Until we have an event,
there is nothing to count, and as a result many of our time periods will end up with zero counts.
Since zero counts contain no real information, we…
Fri, 09/30/2011 - 13:26
All charts for count-based data are charts for individual values. Regardless of whether we are working with a count or a rate, we obtain one value per time period and want to plot a point every time we get a value. This is why four specialty…
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…
Part 2 What 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…
Part One What 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.…
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…
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…
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…
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…