Chapter 3: Quality Management1 Solutions to Chapter 3 Exercises.

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  • Slide 1
  • Chapter 3: Quality Management1 Solutions to Chapter 3 Exercises
  • Slide 2
  • Chapter 3: Quality Management2 Exercise 1
  • Slide 3
  • Chapter 3: Quality Management3 Exercise 2
  • Slide 4
  • Chapter 3: Quality Management4 Exercise 2 continued The upward trend in cancellations and non- renewals is a definite cause for concern.
  • Slide 5
  • Chapter 3: Quality Management5 Exercise 3
  • Slide 6
  • Chapter 3: Quality Management6 Exercise 3 concluded Jun Jul Aug Sep Oct Nov 1.2826 1.02.7574 UCL LCL * * * * * *
  • Slide 7
  • Chapter 3: Quality Management7 Exercise 4 X i 3,500 4,100 3,750 4,300 4,000 3,650 Total 23,300
  • Slide 8
  • Chapter 3: Quality Management8 Exercise 5
  • Slide 9
  • Chapter 3: Quality Management9 Exercise 5 concluded Normally control limits are set at three sigma so any point outside the limits is to be investigated. For limits set at lower sigma values, it should be considered that there is a chance of a random point falling outside the limits even though the process is in control. For one- sigma limits the chance is 32% or one out of three points. For two-sigma limits the chance is 5%, or one point out of twenty. In our case there are 3 points out of twelve, so action should be taken, but if these had been one-sigma limits, action would be unnecessary.
  • Slide 10
  • Chapter 3: Quality Management10 Exercise 6a Day Range Sat 3 Sun 4 Mon 2 Tue 5 Wed 3 Thu 5 Sum 22 For Friday the range is 7, so the range on Friday is in control.
  • Slide 11
  • Chapter 3: Quality Management11 Exercise 6a concluded 9.45 3.67 0 Sat Sun Mon Tue Wed Thu Fri UCL LCL * * * * * * *
  • Slide 12
  • Chapter 3: Quality Management12 Exercise 6b Day Sample Mean Sat 20.3 Sun 19.3 Mon 17.0 Tue 19.0 Wed 21.0 Thu 18.7 Sum 115.3 For Friday the sample mean is 16.7, so the process is in control.
  • Slide 13
  • Chapter 3: Quality Management13 Exercise 6b concluded 22.96 19.21 15.45 Sat Sun Mon Tue Wed Thu Fri UCL LCL * * * * * * *
  • Slide 14
  • 14 Exercise 7 Dough Boys pizza crust production system is not capable of consistently meeting its customer requirements given the C p index of less than 1. Options available to Dough Boy include improving its production system to lower the natural variation in the system. In this case, Dough Boy needs to reduce the standard deviation of pizza crusts from 1.1 to.66 or lower in order to obtain a C p index of 1 or more. Alternatively, Dough Boy could try to convince its customers to increase the range of acceptable pizza crust diameters.
  • Slide 15
  • Chapter 3: Quality Management15 Exercise 8 The C p index indicates that given the natural variation in the filling operation, it is capable of meeting the design specifications. However, when the alignment of the process mean and the design specification is considered, it is found that the filling operation is not capable of consistently meeting design requirements.
  • Slide 16
  • Chapter 3: Quality Management16 Exercise 9a Total number of cases = 27,400 Total incorrect = 235
  • Slide 17
  • Chapter 3: Quality Management17 Exercise 9a concluded.03623.00857 0.0 UCL LCL
  • Slide 18
  • Chapter 3: Quality Management18 Exercise 9b: Day 7 On day 7, p =.0115, therefore process is in control.
  • Slide 19
  • Chapter 3: Quality Management19 Exercise 9b: Day 8 On day 8, p =.0093, therefore process is in control.
  • Slide 20
  • Chapter 3: Quality Management20 Exercise 9b: Day 9 On day 9, p =.0123, therefore process is in control.
  • Slide 21
  • Chapter 3: Quality Management21 Exercise 10 X p c Mon 25.000025 25 Tue 36.000036 36 Wed 17.000017 17 Sum 78.000078 78 Avg. 26.000026 26
  • Slide 22
  • Chapter 3: Quality Management22 Exercise 10: Sample Means Chart A 2 = 1.023; Range 36 - 17 = 19 UCL = 26 + 1.023(19) = 45.44 LCL = 26 - 1.023(19) = 6.56 Thursdays 47 defectives is outside control limits.
  • Slide 23
  • Chapter 3: Quality Management23 Exercise 10: p chart On Thursday, p =.000047, therefore not in control.
  • Slide 24
  • Chapter 3: Quality Management24 Exercise 10: c chart On Thursday, 47 are defective. Thus, out of control.
  • Slide 25
  • Chapter 3: Quality Management25 Exercise 10 concluded The c chart is most appropriate The p chart is acceptable The sample means chart is not appropriate

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