A Sporting Goods Manufacturer Makes Baseballs A)
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Multiple Choice

A sporting goods manufacturer makes baseballs. The target mass of a baseball is 145.5 grams with a standard deviation of ±3.5 grams. A technician selects 100 baseballs at random per hour and records the mean mass of the samples. The table below lists the mass in grams for a 36 hour period.
Determine the most accurate mean control chart drawn from the data shown in the table.
  $\begin{array} { l c c c c c c } \text { Hour } & 1 & 2 & 3 & 4 & 5 & 6 \\& & & & & & \\\text { Mass } & 145.20 & 146.20 & 145.30 & 144.60 & 144.80 & 146.30 \\\text { Hour } & 7 & 8 & 9 & 10 & 11 & 12 \\& & & & & & \\\text { Mass } & 144.80 & 145.00 & 146.10 & 145.40 & 143.70 & 145.10 \\\text { Hour } & 13 & 14 & 15 & 16 & 17 & 18 \\\\\text { Mass } & 146.30 & 145.20 & 145.00 & 145.90 & 146.00 & 145.70 \\\text { Hour } & 19 & 20 & 21 & 22 & 23 & 24 \\\\\text { Mass } & 146.30 & 144.80 & 144.90 & 143.80 & 144.30 & 145.60 \\\text { Hour } & 25 & 26 & 27 & 28 & 29 & 30 \\\\\text { Mass } & 144.80 & 145.70 & 145.80 & 144.60 & 145.30 & 144.90 \\\text { Hour } & 31 & 32 & 33 & 34 & 35 & 36 \\\\\text { Mass } & 146.20 & 146.30 & 144.00 & 145.40 & 144.60 & 145.50\end{array}$

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