The Inability Of $\bar { X }$ Charts with 3-Sigma Limits to Quickly Detect Small Shifts in Limits

question 82

Multiple Choice

The inability of $\bar { X }$ charts with 3-sigma limits to quickly detect small shifts in the process mean has prompted investigators to develop procedures that provide improved behavior in this respect. Which of the following conditions need to be satisfied for an appropriated intervention to take corrective action?

• A) Two out of three successive points fall outside 2-sigma limits on the same side of the center line.
• B) Four out of five successive points fall outside 1-sigma limits on the same side of the center line.
• C) Eight successive points fall on the same side of the center line.
• D) All of the above.
• E) None of the above.

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Definitions:

Variable Cost

Costs that fluctuate with the level of output, such as materials and labor directly involved in production.

Cost Driver

An element that leads to a variation in the expense associated with an action.

Semivariable Cost

Costs that have both fixed and variable components, changing in response to activity level but not directly proportional to it.

Variable Costs

Costs that change in proportion to the level of goods or services produced, including costs for materials and labor directly involved in production.