control chart


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control chart

n
(Statistics) statistics a chart on which observed values of a variable are plotted, usually against the expected value of the variable and its allowable deviation, so that excessive variations in the quality, quantity, etc, of the variable can be detected
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014
References in periodicals archive ?
Shewhart control chart in microbiological quality control of purified water and its use in quantitative risk evaluation.
"Before this techniques was developed by the CRIS (Centre for Railway Information System) in collabration with ISRO, the divisional controls setup for the purpose of train movement control were dependent on the information relayed by the station master to the station controller and the data was fed in the control chart by the section controller manually," he said.
In this case, the standard deviation used defines a reasonably large area to avoid false positives; the moving average, as well as the control chart, was used to define control limits based on difference between two sequential measurements.
Data are collected and analyzed using a control chart. Decisions about actions then can be made.
The utilized CUSUM control chart in the present work is a type of tabular, with individual observations and it works as follows:
SPC includes seven major tools: 1-Histogram or steam-and-leaf plot, 2- check sheet, 3- Pareto chart, 4-cause-and-effect diagram, 5- defect concentration diagram, 6- scatter diagram, and 7- control chart. Elimination of the process variation is the eventual goal of SPC (Montgomery, 2009).
Saleh and Mahmoud [4] claimed that when the estimated process parameters are used in place of the known process parameters, the performance of the control chart is affected due to the existence of variability in the estimation.
Control chart with marked points outside the regulation limits
The usual control chart situation can be applied in the case of an assay with a quantified result, and one or more in-assay control samples which are run on a regular basis.
To specify the criteria for finding a series of points, the area of the individual control chart above the central line and below it is divided into three <<zones>>: A, B and C [4].
Because the mixture control chart patterns (MCCPs) are hidden, it is much more difficult to identify the MCCPs in a complex system [6].