TABLE 18-4
a Factory Supervisor Is Concerned That

question 111

Multiple Choice

TABLE 18-4
A factory supervisor is concerned that the time it takes workers to complete an important production task (measured in seconds) is too erratic and adversely affects expected profits. The supervisor proceeds by randomly sampling 5 individuals per hour for a period of 10 hours. The sample mean and range for each hour are listed below.
$\begin{array}{lll}\text { Hour } &\bar{X} &R\\\hline & & \\1 & 18.4 & 25 \\2 & 16.9 & 27 \\3 & 23.0 & 30 \\4 & 21.2 & 23 \\5 & 21.0 & 24 \\6 & 24.0 & 25 \\7 & 19.3 & 12 \\8 & 15.8 & 14 \\9 & 20.0 & 13 \\10 & 23.0 & 11\end{array}$
She also decides that lower and upper specification limit for the critical-to-quality variable should be 10 and 30 seconds, respectively.

-Referring to Table 18-4, suppose the supervisor constructs an $\bar{X}$ chart to see if the process is in-control. What is the center line of the chart?

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Definitions:

Glorious Revolution

A pivotal event in British history (1688) marking the overthrow of King James II and the establishment of William III and Mary II as co-rulers, leading to the constitutional monarchy.

British Aristocrats

Members of the highest social class in the United Kingdom, traditionally holding hereditary titles and often possessing considerable wealth and influence.

English Monarchy

A system of government in the United Kingdom and its predecessor states where a monarch (king or queen) is the head of state.