I found the following definition of Control limits in the PMBOK glossary.
"The area composed of three standard deviations on either side of the centerline, or mean, of a normal distribution of data plotted on a control chart that reflects the expected variation in the data."
What does the three standard deviations denote? The two control limits UCL and LCL are shown in the control chart diagram. What is the third SD mentioned here?
LCL and UCL basically represents the -3 sigma and +3 sigma respectively. The PMBOK phrase seemed to denote 3 different SD measurements, but it was indeed referring to the 3times sigma value on both sides of mean.
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This interview with Simona Fallavollita (LinkedIn Profile) was recorded at the magnificient Project Management Institute (PMI)® Global Conference 2017 in Chicago, Illinois. We discuss the how, what, why and when of the changes that are coming to the PMP exam.