Four samples of three observations each have been taken, with actual measurements (in centimeters) shown below. Construct three-sigma mean and range charts. $\begin{array}{ccrc}
\text { Sample }\
\begin{array}{ccrc}
\hline 1 & 2 & 3 & 4 \
12.3 & 11.9 & 12.0 & 12.1 \
12.2 & 12.2 & 12.2 & 11.8 \
12.1 & 12.2 & 11.8 & 11.8
\end{array}\end{array}$

$\begin{array}{ccccc}
\text { Sample } & 1 & 2 & 3 & 4 \
\text { Mean } & 12.2 & 12.1 & 12.0 & 11.9 \
\text { Range } & .2 & .3 & 4 & .3
\end{array}$

$\text { Grand mean }=12.05 ; \text { R-bar }=0.3$

Question

Four samples of three observations each have been taken, with actual measurements (in centimeters) shown below. Construct three-sigma mean and range charts. $\begin{array}{ccrc}
\text { Sample }\
\begin{array}{ccrc}
\hline 1 & 2 & 3 & 4 \
12.3 & 11.9 & 12.0 & 12.1 \
12.2 & 12.2 & 12.2 & 11.8 \
12.1 & 12.2 & 11.8 & 11.8
\end{array}\end{array}$

$\begin{array}{ccccc}
\text { Sample } & 1 & 2 & 3 & 4 \
\text { Mean } & 12.2 & 12.1 & 12.0 & 11.9 \
\text { Range } & .2 & .3 & 4 & .3
\end{array}$

$\text { Grand mean }=12.05 ; \text { R-bar }=0.3$

Quizplus · Accepted Answer

The Answer of Four samples of three observations each have been taken, with actual measurements (in centimeters) shown below. Construct three-sigma mean and range charts. $\begin{array}{ccrc}
\text { Sample }\
\begin{array}{ccrc}
\hline 1 & 2 & 3 & 4 \
12.3 & 11.9 & 12.0 & 12.1 \
12.2 & 12.2 & 12.2 & 11.8 \
12.1 & 12.2 & 11.8 & 11.8
\end{array}\end{array}$

$\begin{array}{ccccc}
\text { Sample } & 1 & 2 & 3 & 4 \
\text { Mean } & 12.2 & 12.1 & 12.0 & 11.9 \
\text { Range } & .2 & .3 & 4 & .3
\end{array}$

$\text { Grand mean }=12.05 ; \text { R-bar }=0.3$

Four Samples of Three Observations Each Have Been Taken, with Actual