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Unformatted text preview: remains in control. To evaluate the control of a process with given standards μ and σ, make an x-bar control chart (or x-bar chart) as follows: *Plot the means x-bar of regular samples of size n against time. *Draw a horizontal center line at μ. *Draw horizontal control limits at μ ± 3σ / √(n). Any x-bar that does not fall between the control limits is evidence that the process is out of control. The purpose of a control chart is not to ensure good quality by inspecting most of the items produced. Control charts focus on the process itself rather than on the individual products. All processes have variation. There are two signals indicating that a process is out-of-control. The first is obtaining a sample mean that is below or above .The second signal is having nine sample means in a row either above the center line or below the center line....
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This note was uploaded on 02/27/2012 for the course STAT 121 taught by Professor Patticolling during the Winter '11 term at BYU.
- Winter '11