bkarthikeyan
25th June 2007, 09:48 PM
I want to know where I can use I MR chart? What is the methodology ( Step - by step) ? how to interprete?? If any one can give WI ??
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View Full Version : I MR chart - Methodology needed Steve Prevette 25th June 2007, 10:25 PM I prefer to use the statistical standard deviation formula on my x-individuals charts, but I do have a writeup that refers to it, and writeups on interpreting control charts (and performing the Red Bead Experiment) at http://www.hanford.gov/rl/?page=1144&parent=169 and http://www.hanford.gov/rl/?page=1156&parent=1144 Darius 26th June 2007, 10:32 AM I-MR Chart is documented as usefull for a chemical batch, more or less for continuous data. IMHO, I-MR can be used when there is NO rational subgroups (better than to create rational subgroups from the nothing, altho there can be the oposite idea). The mayor problem for I-MR is that easily can be affected by autocorrelation, Don Wheeler wrote about an autocorrelation factor that can be used. Because of the autocorrelation, it may be expected to show runs pattern at the control chart that can be taken as part from the process it self but not from special (not what is spected to happen) causes. So in those cases ( I-MR charts ) I don't use runs pattern to detect special causes.:rolleyes: pagnonig 4th December 2008, 06:29 AM I-MR Chart is documented as usefull for a chemical batch, more or less for continuous data. IMHO, I-MR can be used when there is NO rational subgroups (better than to create rational subgroups from the nothing, altho there can be the oposite idea). The mayor problem for I-MR is that easily can be affected by autocorrelation, Don Wheeler wrote about an autocorrelation factor that can be used. Because of the autocorrelation, it may be expected to show runs pattern at the control chart that can be taken as part from the process it self but not from special (not what is spected to happen) causes. So in those cases ( I-MR charts ) I don't use runs pattern to detect special causes.:rolleyes: Darius, which is the Dr. Wheeler book where the correlation factor is described? Thank you. bobdoering 4th December 2008, 09:31 AM I want to know where I can use I MR chart? What is the methodology ( Step - by step) ? how to interprete?? If any one can give WI ?? What kind of process are you implementing I MR charting on? Darius 5th December 2008, 10:19 AM ADVANCED TOPICS IN STATISTICAL PROCESS CONTROL (http://www.spcpress.com/Merchant2/merchant.mvc?Screen=PROD&Store_Code=SPI&Product_Code=63-9&Category_Code=) By Donald Wheeler To the adminstrator, Sorry if I comit a fault giving a direction to the book I was asked for (I am not sure),If so Just give the name of the book. A must have. :D But if you want an example just give me some data to play with. pagnonig 5th December 2008, 11:29 AM ADVANCED TOPICS IN STATISTICAL PROCESS CONTROL (http://www.spcpress.com/Merchant2/merchant.mvc?Screen=PROD&Store_Code=SPI&Product_Code=63-9&Category_Code=) By Donald Wheeler To the adminstrator, Sorry if I comit a fault giving a direction to the book I was asked for (I am not sure),If so Just give the name of the book. A must have. :D But if you want an example just give me some data to play with. Unfortunately I don't have significant data for you Darius. Any example on the autocorrelation factor would be really appreciated. In the meantime I'll order the book... :) |
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