Practice questions 1. A controlled process shows an overall mean performance of 2.5 and an average range of 0.42. Samples of size 4 were used to construct the control charts. If specifications are 2.6 +/-0.25, how well can this process meet them? What are the process capability indexes? 2. Suppose that a specification calls for LTL=2 and UTL=6. A sample of 100 parts found average as 4.3 and standard deviation as 0.6. Should the manager consider any actions based on this information? (hint: compute Cp, Cpl, Cpu, Cpk). 3. Calculate sigma level if 26 defects are found in 10 units of a generic product? Sample Control Create the appropriate control chart using the provided data sets: 1. Sample Number 1 2 3 4 5 6 7 8 Sample Thickness (mm) 0.509 0.502 0.521 0.469 0.504 0.505 0.525 0.468 0.489 0.506 0.486 0.497 0.513 0.516 0.482 0.483 0.552 0.516 0.476 0.472 0.480 0.484 0.518 0.510 0.516 0.489 0.513 0.495 0.508 0.499 0.466 0.480 2. Lot Identification Sample Size Constant) Number Defectiv (In the Sample) 1 3 4 5 6 7 3 4 6 6 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 109 4