Question: When do we recalculate the limits in Process Behavior Charts?
A reader asked: “I am wondering at what point do you recommend recalculating the average and upper and lower limits?” Generally, we’d recalculate limits when
Blog: Reader Questions
Question: Do the data have to be normally distributed for Process Behavior Charts to be valid?
A reader asked, “Do the data have to be normally distributed to use a Process Behavior Chart?” The short answer is “no.” Process Behavior Charts,
Question: Why is there a scaling factor for the Upper and Lower Natural Process Limits?
A reader question: “Mark, Thanks to your help, and some push from an IHI conference there is some pull in our organization for Process Behavior
Question: What should the MR-bar be?
This question also came from a webinar viewer: “Second question; how do you tell if a process is “controlled” or not? Is there a sort
Question: Should I be re-evaluating the average and limits every time?
This question came from a webinar viewer: “You said that a minimum of 20 data points is a good place to start in order to
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Hi. I'm Mark Graban
I help businesses leaders and workers improve their activities and processes. With methods grounded in Lean, math and science — backed by data. Better to make choices based on facts — instead of opinions, hunches, or feelings. Learn how to convert data, metrics, and charts into knowledge and wisdom — to chose your next best action. That’s what I do and why I wrote "Measures of Success."