Question about "Common Cause variation"
Submitted by SebastienRol on Fri, 08/22/2014 - 20:00
Hello,
while reading RITA PMP Exam Prep, i read and understand the notion of control limits and "Special cause variation" (outside control limits) and "Normal and expected variation" (within control limits).
In another book, i saw "Common Cause variation" which has not been explained.
Is "Common cause variation" is the same as "Normal and expected variation" (within control limits) ? If not, is "Common cause variation" is a special case of "Special cause variation" ?
Think for help
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Sun, 08/24/2014 - 12:27
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Variation and Cause of
Variation and Cause of variation should not be confused.
There are two kinds of variation, first is called intrinsic or controlled variation, this is due to normal causes , its permanent and do not change in time.
The second kind of variation is uncontrolled, and is due to special causes , which change w.r.t time.