Stop X-bar/R Madness!!
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Be sure to check out my new blog that discusses calculation of unilateral tolerance capability. Capability calculation is not a very powerful index - more of a 30,000 foot view of a process - but calculating the wrong index answers the wrong question. Most people make this mistake, they simply don't know any better. But, take a minute to go through the logic and see where the real endpoint should be! Unilateral Tolerance Capability Calculation