TABLE 18-9
the Manufacturer of Cat Food Constructed Control Charts

TABLE 18-9
The manufacturer of cat food constructed control charts and analyzed several quality characteristics. One characteristic of interest is the weight of the filled cans. The lower specification limit for weight is 2.95 pounds. The table below provides the range and mean of the weights of five cans tested every fifteen minutes during a day's production.
$\begin{array}{cllccc}\hline \text { Number } & \text { XBar } & \text { Range } & \text { Number } & \text { XBar } & \text { Range } \\\hline 1 & 3.05072 & 0.0215 & 16 & 3.04646 & 0.073 \\2 & 3.01228 & 0.087 & 17 & 3.03868 & 0.0696 \\3 & 3.03558 & 0.0851 & 18 & 3.03338 & 0.0329 \\4 & 3.01014 & 0.0674 & 19 & 3.03322 & 0.0455 \\5 & 3.00858 & 0.0983 & 20 & 3.05078 & 0.0215 \\6 & 3.02704 & 0.0527 & 21 & 3.04808 & 0.0396 \\7 & 3.04268 & 0.0508 & 22 & 3.05348 & 0.0581 \\8 & 3.01052 & 0.0791 & 23 & 3.05516 & 0.0682 \\9 & 3.03464 & 0.0663 & 24 & 3.03426 & 0.0325 \\10 & 3.02034 & 0.0538 & 25 & 3.0516 & 0.0641 \\11 & 3.03764 & 0.0584 & 26 & 3.05562 & 0.0809 \\12 & 3.0409 & 0.0434 & 27 & 3.04402 & 0.0374 \\13 & 3.0519 & 0.0762 & 28 & 3.06458 & 0.0284 \\14 & 3.03994 & 0.0833 & 29 & 3.0544 & 0.0738 \\15 & 3.03788 & 0.0601 & & & \\\hline\end{array}$




-Referring to Table 18-9, an $\bar{ X}$ chart is to be used for the weight. One way to obtain the control limits is to take the grand mean and add and subtract the product of A2 times the average of the sample ranges. For this data set, the value of A2 is_____ .