TABLE 17-3
a Quality Control Analyst for a Light Bulb

question 30

Multiple Choice

TABLE 17-3
A quality control analyst for a light bulb manufacturer is concerned that the time it takes to produce a batch of light bulbs is too erratic. Accordingly, the analyst randomly surveys 10 production periods each day for 14 days and records the sample mean and range for each day.

$\begin{array}{lcl} \underline { \text { Day } }& \underline { \bar { X } \text { (in minutes) }} & \underline { R }\\1 & 58.5 & 5.1 \\2 & 47.6 & 7.8 \\3 & 64.3 & 6.1 \\4 & 60.6 & 5.7 \\5 & 63.7 & 6.2 \\6 & 57.5 & 6.0 \\7 & 55.0 & 5.4 \\8 & 54.9 & 6.1 \\9 & 55.0 & 5.9 \\10 & 62.7 & 5.0 \\11 & 61.9 & 7.1 \\12 & 60.0 & 6.5 \\13 & 58.3 & 5.9 \\14 & 52.0 & 5.2\end{array}$

-Referring to Table 17-3, suppose the analyst constructs an $\bar { X }$ chart to see if the production process is in-control. Which expression best describes this chart?

• A) In-control
• B) Increasing trend
• C) Decreasing trend
• D) Individual outliers

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Definitions:

Retinal Disparity

A binocular cue for perceiving depth based on the fact that the two eyes view the world from slightly different angles, creating a disparity that the brain interprets as depth.

Precognition

The phenomenon of knowing or sensing something before it happens, often associated with psychic abilities.

High Need

A strong requirement or desire for something, which could be physical, emotional, or psychological.

Power

The ability or capacity to influence, direct, or control the behavior of others or the course of events.