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Control Plan Problem

Problem #1

According to the control plan, 8 bolts will be measured every half hour and the machine will will be stopped if it is out of adjustment. Ninety-five percent of the bolts should be within 4+ or - .0004 inches. The last act of 8 showed the following measurements:


Should the machine be stopped and reset? About what percentage of the bolts is likely to be beyond the limits the way machine is now running.

Please be specific, one of the problems was determining the standard deviation!

Problem #2

Thirty-five samples of size 7 each were taken from a fertilizer-bag filling machine. The results were: Overall mean= 57.75 lb; Average Range = 1.78 lb.

a) Determine the Upper and Lower Control limits of the X-bar chart, where the standard deviation is 3.

b) Determine the Upper and Lower Control limits of the R-chart, where the standard deviation is 3

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Solution Summary

This solution solves 2 statistics problems that address upper limit, lower limit, sample, standard deviation, percentage, range, average and mean.