Charles P. Quesenberry

The Effect of Sample Size on Estimated Limits for and X Control Charts

The results of this study indicate that charts with subgroups of size n require about 400/(n-1) samples, and X charts require about 300 values to estimate control limits that perform like known limits. The results also indicate that using estimated con..

SPC Q charts for start-up processes and short or long runs

Classical control charts are designed for processes where data to estimate the process parameters and compute the control limits are available before a production run. For many processes, especially in a job-shop setting, production runs are not necessa..

ON PROPERTIES OF Q CHARTS FOR VARIABLES

The sensitivity of four tests on Shewhart type Q charts and of specially designed EWMA and CUSUM Q charts to detect one-step permanent shifts of either a normal mean or standard deviation has been studied. The usual test that signals for one point beyon..

Geometric Q Charts for High Quality Processes

The geometric distribution based on the inverse binomial method of sampling is used to define Q statistics for the case when the process fallout p is known and when it is not known in advance of sampling. The effectiveness to detect shifts in p of four ..

Power studies of some tests for uniformity

Results from a simulation study of the power of eight statistics for testing that a sample is form a uniform distribution on the unit interval are reported. Power is given for each statistic against four classes if alternatives. The statistics studied include the discrete Pearson chi-square with ten and twenty cells, X2 10 and X2 20; Kolmogorov-smirov, D; Cramer-Von Mises, W2; Watson, U2; Anderson-Darling, A; Greenwood. G;and a new statistic called O A modified form of each of these statistic is also studied by first transforming the sample using a transformation given by Durbin. On the basis of the results observed in this study, the Watson U2 statistic is recommended as a general test for uniformity.

SPC Q Charts for a Poisson Parameter Lambda: Short or Long Runs

Approximately normalized control charts, called Q Charts, have been given by the author in other work for charting variables and for a binomial attributes chart. We consider here the corresponding ...

An SPC Approach to Compensating a Tool-Wear Process

A fixed-interval compensator is proposed for a process where tool wear can be modeled over an interval of tool life by a regression model. The compensator consists of a batch mean adjustment plus the estimated wear since the last adjustment. The expecte..

Transforming samples from truncation parameter distributions to uniformity

Transformations are given which transform a sample from an arbitrary member of a parametric family with range and density from dependent upon parameters to aset of i.i.d uniform rvs on (0,1). The two-parameter exponential, Pareto and uniform distributions are considered in examples.

On Properties of Binomial Q Charts for Attributes

The sensitivity of four tests on Shewhart Q charts and of specifically designed exponentially weighted moving average (EWMA) and cumulative sum (CUSUM) Q charts to detect one-step permanent shifts of a binomial probability parameter p has been studied. ..

ON PROPERTIES OF POISSON Q CHARTS FOR ATTRIBUTES

The sensitivity of four tests on Shewhart Q charts and of specially designed EWMA and CUSUM Q charts to detect one-step permanent shifts of a Poisson parameter has been studied. The usual test that signals for one point beyond three standard deviations ..