S
SPC_Newbie
Hello,
I've played with some data in a speadsheet but have no idea if I've even come close to to calculating Cs properly.
I also don't know what a good number looks like - woul it be similar to Cp, meaning am I looking for a 1.33 or better? How would we calculate control limits?
Does anyone have a spreadsheet that does the calculation? I'm very interested in any known test data and results someone might have so I can prove out my sheet/calculations.
I'm using the calculation: Cs = min{USL - Mean, Mean-LSL}/{3*[sigma^2+(Mean-Target)^2+abs(3rd_Moment/sigma)]} (thanks Darius!)
Attached is my worksheet. Am I even close??
I kind of put it together leveraging information from a you tube video as this formula is my first introduction to moments/skew/kurtosis:
SIDE NOTE: I've searched for an article I had been pointed to before (EVALUATION OF PROCESS CAPABILITY INDEX FOR NON-NORMAL DISTRIBUTIONS) but have not turned it up.
I've played with some data in a speadsheet but have no idea if I've even come close to to calculating Cs properly.
I also don't know what a good number looks like - woul it be similar to Cp, meaning am I looking for a 1.33 or better? How would we calculate control limits?
Does anyone have a spreadsheet that does the calculation? I'm very interested in any known test data and results someone might have so I can prove out my sheet/calculations.
I'm using the calculation: Cs = min{USL - Mean, Mean-LSL}/{3*[sigma^2+(Mean-Target)^2+abs(3rd_Moment/sigma)]} (thanks Darius!)
Attached is my worksheet. Am I even close??
I kind of put it together leveraging information from a you tube video as this formula is my first introduction to moments/skew/kurtosis:
SIDE NOTE: I've searched for an article I had been pointed to before (EVALUATION OF PROCESS CAPABILITY INDEX FOR NON-NORMAL DISTRIBUTIONS) but have not turned it up.