Section: Volume D
Explanation:
Control charts, are used to determine whether or not a process is stable or has predictable performance.
Upper and lower specification limits are based on requirements of the agreement. They reflect the maximum and minimum values allowed. There may be penalties associated with exceeding the specification limits. Upper and lower control limits are different from specification limits. The control limits are determined using standard statistical calculations and principles to ultimately establish the natural capability for a stable process. The project manager and appropriate stakeholders may use the statistically calculated control limits to identify the points at which corrective action will be taken to prevent unnatural performance. The corrective action typically seeks to maintain the natural stability of a stable and capable process. For repetitive processes, the control limits are generally set at ±3 s around a process mean that has been set at 0 s. A process is considered out of control when: (1) a data point exceeds a control limit; (2) seven consecutive plot points are above the mean; or (3) seven consecutive plot points are below the mean. Control charts can be used to monitor various types of output variables.
Although used most frequently to track repetitive activities required for producing manufactured lots, control charts may also be used to monitor cost and schedule variances, volume, and frequency of scope changes, or other management results to help determine if the project management processes are in control.

Section: Volume D

Section: Volume D
Explanation:
A rough order of magnitude (ROM) estimate is the least accurate estimate. A Guide to the Project Management Body of Knowledge (The PMBOK Guide), 5th Edition gives the guidelines that ROMs are -50% to +50% accurate, the PMBOK Guide 5th Edition gives the guidelines that ROMs are -25% to +75% accurate, or potentially even larger. It should be noted that stated percentages are not the main takeaway are not likely specifically tested on; it is more the concept and idea that ROMs are a rough estimate, are used early in the project when info is limited, and are hence the least accurate.