SCENARIO 15-4
a Factory Supervisor Is Concerned That the Time

question 235

Multiple Choice

SCENARIO 15-4
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.
$$\begin{array} { cc c } \underline { \text { Hour } } & \underline { X } & \underline { R } \\1 & 18.4 & 25 \\2 & 16.9 & 27 \\3& 23.0 & 30 \\4 & 21.2 & 23 \\5 & 21.0 & 24 \\6 & 24.0 & 25 \\7&19.3&12\\8 & 15.8 & 14 \\9 & 20.0 & 13 \\10 & 23.0 & 11\end{array}$$ She also decides that lower and upper specification limit for the critical-to-quality variable should be
10 and 30 seconds, respectively.
-Referring to SCENARIO 15-4, suppose the sample mean and range data were based on 6 observations per hour instead of 5.How would this change affect the lower and upper control limits of an R chart?

• A)LCL would increase; UCL would decrease.
• B)LCL would remain the same; UCL would decrease.
• C)Both LCL and UCL would remain the same.
• D)LCL would decrease; UCL would increase.

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Definitions:

Pioneer Species

Species that can colonize a new habitat.

Keystone Species

A species that has a disproportionately large effect on community structure relative to its abundance.

Evolved

The process through which species undergo changes over time, often through genetic variation and natural selection, leading to adaptations and diversity among organisms.

Competitive Exclusion

A principle stating that two species competing for the same resources cannot stably coexist if other ecological factors are constant; one will always outcompete the other.