Instruction 18-15
the Manufacturer of Canned Food Constructed Control Charts

Instruction 18-15
The manufacturer of canned food constructed control charts and analysed several quality characteristics.One characteristic of interest is the weight of the filled cans.The lower specification limit for weight is 2.95 kilograms.The table below provides the range and mean of the weights of five cans tested every 15 minutes during a day's production.
$\begin{array}{|l|l|l|l|l|l|}\hline \text { Number } & \text { XBar } & \text { Range } & \text { Number } & \text { XBar } & \text { Range } \\\hline 1& 3.05072 & 0.0215 & 16 & 3.04646 & 0.073 \\\hline 2 & 3.01228 & 0.087 & 17 & 3.03868 & 0.0696 \\\hline 3 & 3.03558 & 0.0851 & 18 & 3.03338 & 0.0329 \\\hline 4 & 3.01014 & 0.0674 & 19 & 3.03322 & 0.0455 \\\hline 5 & 3.00858 & 0.0983 & 20 & 3.05078 & 0.0215 \\\hline 6 & 3.02704 & 0.0527 & 21 & 3.04808 & 0.0396 \\\hline 7& 3.04268 & 0.0508 & 22 & 3.05348 & 0.0581 \\\hline 3 & 3.01052 & 0.0791 & 23 & 3.05516 & 0.0682 \\\hline 9 & 3.03464 & 0.0663 & 24 & 3.03426 & 0.0325 \\\hline 10 & 3.02034 & 0.0538 & 25 & 3.0516 & 0.0641 \\\hline 11 & 3.03764 & 0.0584 & 26 & 3.05562 & 0.0809 \\\hline 12 & 3.0409 & 0.0434 & 27 & 3.04402 & 0.0374 \\\hline 13 & 3.0519 & 0.0762 & 28 & 3.06458 & 0.0284 \\\hline 14 & 3.03994 & 0.0833 & 29 & 3.0544 & 0.0738 \\\hline 15 & 3.03788 & 0.0601 & & &\\\hline\end{array}$
-Referring to Instruction 18-15,an R chart is to be constructed for the weight.The center line of this R chart is located at ________.