(Situation F) Ten Samples Of $n = 5$ Were Collected to Construct An

Multiple Choice

(Situation F) Ten samples of $n = 5$ were collected to construct an $\bar { R }$ -chart. The sample means and ranges for the 10 samples are shown below.


$\begin{array}{cccccc}\hline \text { Sample } & \text { Mean } & \text { Range } & \text { Sample } & \text { Mean } & \text { Range } \\\hline 1 & 20.2 & 2.7 & 6 & 20.4 & 1.9 \\2 & 22.4 & 1.8 & 7 & 15.9 & 1.0 \\3 & 21.2 & 1.5 & 8 & 22.3 & 2.1 \\4 & 18.2 & 1.2 & 9 & 20.7 & 1.6 \\5 & 23.2 & 2.4 & 10 & 21.1 & 1.8\end{array}$
-Calculate the centerline of the $\text { R-chart. }$

A) 1.0386
B) 2.057
C) 1.80
D) 4.114