Aspen Plastics produces plastic bottles to customer order. The quality inspector randomly selects four bottles from the bottle machine and measures the outside diameter of the bottle neck, a critical quality dimension that deter- mines whether the bottle cap will fit properly. The dimen- sions (in.) from the last six samples are BOTTLE Sample 1234 1 0.594 0.622 0.598 0.590 2 0.587 0.611 0.597 0.613 3 0.571 0.580 0.595 0.602 4 0.610 0.615 0.585 0.578 5 0.580 0.624 0.618 0.614 6 0.585 0.593 0.607 0.569
a. Assume that only these six samples are sufficient, and use the data to determine control limits for an R- and an x-chart.