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 under 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: $$\begin{array} { r }
{ \text { Weight (ounces) } }\
\begin{array} { l l l l l }
\text { Day } \
\hline \text { Monday } & 23 & 22 & 23 & 24 \
\text { Tuesday } & 23 & 21 & 19 & 21 \
\text { Wednesday } & 20 & 19 & 20 & 21 \
\text { Thursday } & 18 & 19 & 20 & 19 \
\text { Friday } & 18 & 20 & 22 & 20
\end{array}\end{array}$$ 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

Question

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 under 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: $$\begin{array} { r } 
{ \text { Weight (ounces) } }\
\begin{array} { l l l l l } 
\text { Day } \
\hline \text { Monday } & 23 & 22 & 23 & 24 \
\text { Tuesday } & 23 & 21 & 19 & 21 \
\text { Wednesday } & 20 & 19 & 20 & 21 \
\text { Thursday } & 18 & 19 & 20 & 19 \
\text { Friday } & 18 & 20 & 22 & 20
\end{array}\end{array}$$ 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

Quizplus · Accepted Answer

The Answer of 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 under 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: $$\begin{array} { r } 
{ \text { Weight (ounces) } }\
\begin{array} { l l l l l } 
\text { Day } \
\hline \text { Monday } & 23 & 22 & 23 & 24 \
\text { Tuesday } & 23 & 21 & 19 & 21 \
\text { Wednesday } & 20 & 19 & 20 & 21 \
\text { Thursday } & 18 & 19 & 20 & 19 \
\text { Friday } & 18 & 20 & 22 & 20
\end{array}\end{array}$$ 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

A Quality Analyst Wants to Construct a Sample Mean Chart