Ten Samples of N = 5 Were Collected to Construct $\overline { x ^ { * } }$

Multiple Choice

Ten samples of n = 5 were collected to construct an $\overline { x ^ { * } }$ chart. The sample mean and range for each sample are shown in the table below. $$\begin{array} { | c c c | c c c | } \hline \text { Sample } & \text { Mean } & \text { Range } & \text { Sample } & \text { Mean } & \text { Range } \\\hline 1 & 215 & 15 & 6 & 224 & 21 \\2 & 204 & 20 & 7 & 205 & 27 \\3 & 160 & 10 & 8 & 184 & 12 \\4 & 226 & 19 & 9 & 207 & 16 \\5 & 232 & 24 & 10 & 212 & 17 \\\hline\end{array}$$ Calculate the empirical centerline for the R chart.

A) 20.8
B) 17.2
C) 18.1
D) 19.4