Question

25% (5) A precision machine shop is involved in mass production of small shafts for a precision electromechancial device. A quality assurance engineer is assigned with the responsībility of establishing quality control charts. She took five samples from the batch of 500 shafts produced by one lathe. The diameters that she measured from three selected locations along the length of each of these saraples are listed below: Sample No. Diameter at position1Diameter at position 2Diameter at position 3 3.25 3.16 2.40 4 3.10 Unit: mm (a) Determine the statistical mode of all the measured data (b) The median and mean of all measured data (c) The standard deviation of the measured data and its physical me (d) The control chart by the 3-Sigma method (e) The control chart based on sample ranges (f) How would the quality assurance engineer use these charts in her controlling the quality of shafts produced by that particular machine? (g) Comment on the fitness of the measured data to a normal distribution curve (h) How would she improve the credibility of the control charts that she has established in (d) and (e)?

Answer 1