A Quality Analyst Wants to Construct a Sample Mean Chart

question 86

Multiple Choice

A quality analyst wants to construct a sample mean chart for controlling a packaging process. He knows from past experience that whenever this process is in control, package weight is normally distributed with a mean of 20 ounces and a standard deviation of two ounces. Each day last week, he randomly selected four packages and weighed each: $$\begin{array} { l l c c c } \text { Day } & &{ \text { Weight (ounces) } } \\\hline \text { Monday } & 23 & 22 & 23 & 24 \\\text { Tuesday } & 23 & 21 & 19 & 21 \\\text { Wednesday } & 20 & 19 & 20 & 21 \\\text { Thursday } & 18 & 19 & 20 & 19 \\\text { Friday } & 18 & 20 & 22 & 20\end{array}$$
If he uses upper and lower control limits of 22 and 18 ounces, what is his risk (alpha) of concluding this process is out of control when it is actually in control (Type I error) ?

• A) 0.0026
• B) 0.0456
• C) 0.3174
• D) 0.6826
• E) 0.9544

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Definitions:

Dental Hygiene

The practice of keeping one’s mouth clean and free of disease and other problems by regular brushing and cleaning between the teeth.

True Obedience

The genuine compliance with commands or demands from an authority figure, often studied in the context of social psychology.

Compliance

The act of agreeing with or obeying a request, command, or set of standards.

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Social groups that individuals compare themselves to for the purpose of evaluating their own behaviors, attitudes, and beliefs.