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*AzCivic* · 09-13-2005, 07:38 PM

they way i just learned is that the control limits are either set by the instructor or are +/- 2.66times(average of the moving ranges) and "moving range" being the absolute value of the difference between two consecutive data points plotted in the trend chart.

then there's some other control limits that are for ideal cases(which i think is yours)that are +/- (#ofS.D.'s), which i think is what you need. so put all your data in an excel spread sheet make it tell you the standard deviation and I think your control limits would be +/-(4 times whatever# excel gives you).

i could be wrong but i dont think i am.

09-13-2005, 07:38 PM	#6
AzCivic Moderator Join Date: Feb 2002 Location: Az Age: 43 Posts: 3,804	they way i just learned is that the control limits are either set by the instructor or are +/- 2.66times(average of the moving ranges) and "moving range" being the absolute value of the difference between two consecutive data points plotted in the trend chart. then there's some other control limits that are for ideal cases(which i think is yours)that are +/- (#ofS.D.'s), which i think is what you need. so put all your data in an excel spread sheet make it tell you the standard deviation and I think your control limits would be +/-(4 times whatever# excel gives you). i could be wrong but i dont think i am.