QUESTION 750 In which process would you be most likely use variable [or attribute, for that matter] sampling?
Variable (sometimes variables) sampling involves products or processes that are measured over a range (or variety) of numbers. For example, the percentage of salt content on potato chips, the depth of concrete for a new highway, the size of the gap between a car door and body for car manufacturers or the length of time it takes a page to load on a web site. Usually, as in the first three cases, the goal is to hit a target. In other words: (still talking variable sampling) the potato chip maker wants a target amount of salt on the chip, say 2%. More is bad (for health purposes) and less is bad (for taste purposes). If the depth of highway concrete is supposed to be 11 inches, more is bad (waste) and less is bad (early deterioration). In the case of the web site page loading, shorter is better, but we still measure the results over a range of possibilities, say from 1 to 30 seconds, so our sampling procedure will use variable sampling. Variable Sampling Examples (actual increments will vary) Chips: 1.8%, 1.9%, 2.0%, 2.1%, and 2.2%Concrete: 10.0″, 10.5″, 11.0″, 11.5″, and 12.0″ Web page loading: 1 sec, 2 sec, 3 sec, etc. Attribute sampling involves a yes/no or binary decision. The product has the characteristic (usually a defect) or it doesn’t. Attribute sampling is often done in batches of 50. For example, taking 50 bolts off the assembly line to check for defective threads. Or examine 50 out of a thousand lines of code at random to check for mistakes. When the product or service is examined, it will either exhibit the attribute being investigated or not. For example, it either has a mistake or doesn’t have a mistake. Dr. Deming’s Red Bead Experiment was an example of attribute sampling. Volunteers from the workshop would dip a paddle with 50 depressions into a bunch of red and white beads. White beads were good, red beads represented defects. The results of these two types of sampling are usually plotted on a control chart. Control charts are also only used in 8.3 Quality Control, according to PMI. To summarize, I’ll write a couple more sample questions.
QUESTION 769 You are managing a large project with 20 key internal stakeholders, eight contractors, and six team leaders. You must devote attention to effective integrated change control. This means you are concerned primarily with______________.
Explanation/Reference: Explanation: Performing integrated change control consists of coordinating and managing changes across the project. Activities that occur within the context of perform integrated change control include: validate scope, control scope, control schedule, control costs, perform quality assurance, control quality, manage the project team, control communications, control risks, conduct procurements, control procurements, manage stakeholder engagement, and control stakeholder engagement.
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