SCENARIO 15-3
a Quality Control Analyst for a Light Bulb

question 213

Multiple Choice

SCENARIO 15-3
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.
$\begin{array}{ccc}\underline{\text { Day }}&\underline{ \bar{X} \text { (inminutes) }}& \underline{\text { R}}\\1 & 58.5 & 5.1 \\2 & 47.6 & 7.8 \\3 & 64.3 & 6.1 \\4 & 60.6 & 5.7 \\5 & 63.7 & 6.2 \\6 & 57.5 & 6.0 \\7 & 55.0 & 5.4 \\8 & 54.9 & 6.1 \\9 & 55.0 & 5.9 \\10 & 62.7 & 5.0 \\11 & 61.9 & 7.1 \\12 & 60.0 & 6.5 \\13 & 58.3 & 5.9 \\14 & 52.0 & 5.2\end{array}$
-Referring to SCENARIO 15-3, suppose the analyst constructs an R chart to see if the variability in production times is in-control.What is the lower control limit for this R chart?

• A)4.84
• B)3.37
• C)2.98
• D)1.34

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Definitions:

American Medical Association

The largest association of physicians and medical students in the United States, dedicated to promoting the art and science of medicine for better public health.

American Workers

Employees in the United States who contribute to the country's economy through various sectors and industries.

Unemployed

Individuals who are jobless, actively seeking work, and available to take up employment, usually measured as a percentage of the labor force.

1932

A significant year marked by the election of Franklin D. Roosevelt as President of the United States and the depths of the Great Depression.