Question

The data shown in the table below are i and R values for 24 samples of size n-5 taken from a process producing bearings. The measurements are made on the inside diameter of the bearing. with only the last three decimals recorded (fi.e., 34.5 should be 0.50345). Sample i Number Sample R Number 13 14 15 16 17 18 19 20 21 35.4 34.0 37.1 34.9 33.5 31.7 34.0 35.1 33.7 32.8 33.5 345 34.2 31.6 315 35.0 34.1 32.6 33.8 34 3 33.6 31.9 10 23 12 386 (a) (10 points) Setup i chart and R charts on this peocess. You may use Excel to calculate the center line, UCL and LCL. and to draw the control charts. (Note: do not use Minitab to solve this problem.) (b) (5 points) Does the process seem to be in statistical control? How do you know? (e) (10 points) If necessary, revise the trial control limits by removing the points that fall out the first control limits and recalculate the new control limits. Has the changes made any difference? (d) (5 points) If specifications on this diameter are 0.5030 +0.0010, find the percentage of nonconforming bearings produced by this process. Assume that diameter is normally distributed.