Capability indexes allow us to characterize the relationship between the process potential and the specifications. Performance indexes characterize the past performance relative to the ... [Read More]
Evidently Steven Ouellette did not like my June column, “Is the Part in Spec?” The adjectives he used were “complicated,” “unhelpful,” “backward,” “confusing,” ... [Read More]
During the past 20 years it has become fashionable to condemn measurement processes that are less than perfect. Yet the reality is that we must always use imperfect data. Given this fact of life, ... [Read More]
Having an effective model for the nature of data will inevitably identify two different paths to process improvement. One path seeks to operate a process up to its full potential while the other ... [Read More]
Having an effective model for the nature of data will inevitably identify two different paths to process improvement. One path seeks to operate a process up to its full potential while the other ... [Read More]
Courses in statistics generally emphasize the problem of inference. In my December column, “The Four Questions of Data Analysis,” I defined this problem in the following manner: ... [Read More]
In the 1940s the War Production Board trained approximately 50,000 individuals in how to use process behavior charts (also known as control charts). At that time the computations were done by hand, ... [Read More]
In my column of Jan. 7, “The Right and Wrong Ways of Computing Limits ,” I looked at the problems in computing limits for average charts. This column will consider the right and wrong ways of ... [Read More]
Today virtually everyone uses software to create process behavior charts, yet the available software is notoriously unreliable in terms of the way the limits are computed. This column will explain ... [Read More]
The four questions of data analysis are the questions of description, probability, inference, and homogeneity. Any data analyst needs to know how to organize and use these four questions to be able ... [Read More]
