The use of cumulative sums for detection of changepoints in the rate parameter of a Poisson Process
Computational Statistics & Data Analysis
Adaptive CUSUM procedures with Markovian mean estimation
Computational Statistics & Data Analysis
Optimization designs of the combined Shewhart-CUSUM control charts
Computational Statistics & Data Analysis
Shewhart-type control charts for variation in phase I data analysis
Computational Statistics & Data Analysis
New EWMA control charts for monitoring process dispersion
Computational Statistics & Data Analysis
Computational Statistics & Data Analysis
Evaluation of exponentially weighted moving variance control chart subject to linear drifts
Computational Statistics & Data Analysis
Optimal design of the double sampling X chart with estimated parameters based on median run length
Computers and Industrial Engineering
On efficient use of auxiliary information for control charting in SPC
Computers and Industrial Engineering
Hi-index | 0.03 |
The EWMA chart for the standard deviation is a useful tool for monitoring the variability of a process quality characteristic. The performance of this chart is usually evaluated under the assumption of known parameters. However, in practice, process parameters are estimated from an in-control Phase I data set. A modified EWMA control chart is proposed for monitoring the standard deviation when the parameters are estimated. The Run Length properties of this chart are studied and its performance is evaluated by comparing it with the same chart but with process parameters assumed known.