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Determining Process Capability
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Say for e.g. am collecting effort variance by Week End as Subgroup for several Projects
This is a sample
I calculate the UCL, LCL. I want to calculate K
The estimator for Cpk can also be expressed as Cpk = Cp(1-k), where k is a scaled distance between the midpoint of the specification range, m, and the process mean,mew .
Denote the midpoint of the specification range by m = (USL+LSL)/2. The distance between the process mean,mew , and the optimum, which is m, is mew - m, where .
UCL,LCL and mew are for the POPULATION
In this i think i have to assume a UCL, LCL, T and mew for population & find k. Am i right. If so what sort of values i can assume if say:
the std dev=1.89 & mean=9.74 for the sample
Also after determining k how can i determine mean and std dev to be targeted, in order to achieve the same process capability