A Quality Analyst Wants to Construct a Sample Mean Chart

question 52

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, on what day(s) , if any, does this process appear to be out of control?

• A) Monday
• B) Tuesday
• C) Monday and Tuesday
• D) Monday, Tuesday, and Thursday
• E) None

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Definitions:

Iso-profit Line

A graphical representation in operations research and economics indicating all combinations of two products that generate the same level of profit.

Optimum

The most advantageous condition or degree of something, where the best possible outcome is achieved.