Assignment 9 Control Charts, Process capability and QFD

Instructions: 1. Total No. of Questions: 25. Each question carries one point. 2. All questions are objective type. Only one answer is correct per numbered item.

1. How do you find the process capability?

a) By Process Capability Ratio = Cp = 𝑈𝑈𝑈𝑈𝑈𝑈−𝐿𝐿𝐿𝐿𝐿𝐿 b) By USL and LSL only 6𝜎𝜎 c) By normal distribution curve d) By spread and mean shift of the process

2. In a certain process it is given that USL is 14, LSL is zero. The process has a mean of 10 and standard deviation 2. What will be the Process Capability Ratio? a) 0.83 b) 1.17 c) 1.33 d) 1.5

3. In a process the inverse of process capability ratio is 0.65. Which statement is correct? a) The process is capable. b) The process is incapable. c) The process is capable with tight control. d) None of the above

4. A process having mean 8.80 and process standard deviation 0.12 has spread of specification limit: 9.0±0.4. What will be the process capability index? a) 0.55 b) 1.67 c) 1.33 d) 0.83

5. How is different than ? a) Looks at the centrality of the process. 𝐶𝐶𝑝𝑝𝑝𝑝 𝐶𝐶𝑝𝑝 b) Looks at the overall variability of the process. 𝐶𝐶𝑝𝑝 c) Both look at the overall variability of the process. 𝐶𝐶𝑝𝑝𝑝𝑝 d) Looks at the centrality of the process.

𝐶𝐶𝑝𝑝𝑝𝑝

6. A QC scheme is in operation for a process producing ball-bearings. A sample of 6 bearings is taken every hour and diameters is measured. The mean diameter which the process delivers is 2 cm. A bearing meets specification within the range 1.998cm– 2.002cm. If the specification limits are considered at 1 level, what is the Process Capability? 𝜎𝜎 a) 0.11 b) 0.44 c) 0.22 d) 0.33

7. What is true about Process Capability Index (Cpk) and Process Performance Index (Ppk)?

I. Cpk tells you about what the process is CAPABLE of doing in future, assuming it

remains in a state of statistical control. Ppk tells you how the process has performed in the past and verifies is the process capable to meet Customer CTQs (requirements).

II. Ppk only applies to a specific batch of material.

III. Ppk generally uses sample sigma in its calculation; Cpk uses the process sigma value determined from either the Moving Range, Range or Sigma control charts IV. Both the indexes are same

a) I, II, III are correct b) I and II are correct c) IV is correct d) All are correct

8. A process is having net weight specifications 9.0± 0.5 with process mean 8.80 and standard deviation 0.12.The sample standard deviation is 0.11. What will be the process performance capability? a) 0.83 b) 0.90 c) 1.94 d) 2.12

9. How Quality Function Deployment differs from conventional product development? a) It listens to the customer. b) It develops and manufacture towards measured goals. c) It optimises products and processes. d) All of the above

10. If a Company is late to market to deliver its product by 4 months in ship building industry a) Gross profit potential is reduced by 18%. b) Gross profit potential is reduced by 33%. c) Gross profit potential is reduced by 25%. d) Gross profit potential is reduced by 13%.

11. What does the roof of the House of Quality indicate? a) The customer requirements b) The correlationship matrix showing the conflicts between engineering characteristics. c) The relationship matrix between customer requirement and engineering characteristics d) The target value of the organisation for the product

12. What is the output from 2nd phase of QFD? a) Design Requirements b) Process Operations c) Part/Item Characteristics d) Operations Requirements

13. How Kano Model is different than QFD? a) QFD gives information about delighted needs b) QFD distinguishes the quality of requirements c) Kano Model captures the Voice of the customer d) Kano Model captures the Mind of the customer

14. Which of the following statement is true regarding Kano Model? a) Threshold attributes are those for which more is generally better. b) Performance attributes are the expected attribute that must be there in a product. c) Excitement attributes are unspoken and unexpected by customer. d) None of the above

15. Which of the following statements is incorrect? Quality Function Deployment (QFD)…. a) Reduces product development cycle time b) Increases engineering changes c) Reduces start-up cost d) Helps to identify specific competitive advantages easily

16. Which step is out of DMAIC? a) Measure b) Improvement c) Control d) Design

17. Which of the following statements are true about the Value Stream Map? I. Links the material and information flows II. Ties together lean concepts and techniques III. Less useful than quantitative tools a) Only III b) I and II c) Only II d) I and III

18. Checkout time at a supermarket is monitored using a range and mean chart. Six samples which contain 20 observations per sample have been collected and the sample means and sample ranges have been computed as shown below. Sample Mean Range 1 3.06 0.42 2 3.15 0.50 3 3.11 0.41 4 3.13 0.46 5 3.06 0.46 6 3.09 0.45

Which chart should be used first to analyse the checkout time variability? a) U chart b) X bar chart c) Mean chart d) Range chart

19. Which chart is used when the control chart is having quality characteristics as attributes and defective with constant sample size? a) p chart or np chart b) c chart or u chart c) X bar chart and R chart d) X bar chart and s chart

20. What are the formulae used to find the control limits in u chart? a) = + 3 = 3 𝑢𝑢 𝑢𝑢� 𝑛𝑛𝑖𝑖 𝑛𝑛𝑖𝑖 b) 𝑈𝑈𝑈𝑈𝑈𝑈 = 𝑢𝑢� + 3� ,𝐿𝐿𝐿𝐿𝐿𝐿 =𝑢𝑢� − 3� 𝑢𝑢 𝑢𝑢 𝑈𝑈𝑈𝑈𝑈𝑈 𝑢𝑢� 𝑛𝑛𝑖𝑖 𝐿𝐿𝐿𝐿𝐿𝐿 𝑢𝑢� − 𝑛𝑛𝑖𝑖 c) = + 3� , = 3� 𝑢𝑢� 𝑢𝑢 𝑈𝑈𝑈𝑈𝑈𝑈 𝑢𝑢� 𝑛𝑛𝑖𝑖 𝐿𝐿𝐿𝐿𝐿𝐿 𝑢𝑢� − 𝑛𝑛𝑖𝑖 d) = + 3� , = 3� 𝑢𝑢� 𝑢𝑢� 21. Mean values𝑈𝑈 𝑈𝑈and𝑈𝑈 ranges𝑢𝑢� �of𝑛𝑛 𝑖𝑖da𝐿𝐿𝐿𝐿𝐿𝐿ta from𝑢𝑢� 20− samples�𝑛𝑛𝑖𝑖 (sample size=4) are shown in the table below. S.N Mean of Sample Range S.N Mean of Sample Range 1 10 4 11 12 5 2 15 4 12 13 4 3 12 5 13 12 4 4 11 4 14 12 3 5 9 5 15 11 3 6 11 6 16 15 4 7 11 4 17 12 4 8 9 4 18 15 3 9 10 4 19 11 3 10 11 6 20 10 4

What are the central line and control limits of R chart?

a) Central Line = 4.15, UCL = 9.47 and LCL = 0.00 b) Central Line = 3.57, UCL = 6.87 and LCL = 0.33 c) Central Line = 4.15, UCL = 7.44 and LCL = 0.48 d) Central Line = 4.15, UCL = 9.87 and LCL = 0.00

22. Mean values and ranges of data from 20 samples (sample size = 4) are shown in the table below. S.N Mean of Sample Range S.N Mean of Sample Range 1 10 4 11 12 5 2 15 4 12 13 4 3 12 5 13 12 4 4 11 4 14 12 3 5 9 5 15 11 3 6 11 6 16 15 4 7 11 4 17 12 4 8 9 4 18 15 3 9 10 4 19 11 3 10 11 6 20 10 4

What are the central line and control limits of X bar chart?

a) Central Line = 13.6, UCL = 15.83 and LCL = 8.57 b) Central Line = 11.6, UCL = 14.63 and LCL = 8.57 c) Central Line = 11.6, UCL = 14.63 and LCL = 9.45 d) Central Line = 13.6, UCL = 15.63 and LCL = 9.47

23. A bank manager receives a certain number of complaints each day about the bank’s service. Complaints for 14 days are given in the table shown. Find out the upper control limit and lower control limit using three-sigma limits. (Hint: use c chart) Days Number of Complaints 1 5 2 4 3 3 4 6 5 2 6 5 7 4 8 7 9 6 10 5 11 4 12 2 13 3 14 1

a) UCL is 8 and LCL is 0 b) UCL is 10 and LCL is -2 c) UCL is 8 and LCL is -2 d) UCL is 10 and LCL is 0

24. Match the following 1. X-bar and R charts a) Binomial Distribution 2. p charts b) Poisson Distribution 3. c charts c) Normal Distribution

a) 1-c,2-b,3-a b) 1-b,2-a,3-c c) 1-c,2-a,3-b d) 1-b,2-c,3-a

25. A QC manager counted the number of defective nuts produced by an automatic machine in 12 samples. Using the data given in table below, calculate the upper limit and lower limit of the control chart that will describe 99.74% of the chance variation when the process in control. Each sample contained 200 nuts.

Samples Number of Defects 1 12 2 14 3 13 4 10 5 12 6 11 7 14 8 12 9 14 10 9 11 13 12 10

a) UCL is 0.05136 & LCL is 0.02124 b) UCL is 0.11037 & LCL is 0.00963 c) UCL is 0.18634 & LCL is 0.00357 d) UCL is 0.27963 & LCL is 0.00014

Answer Key

1 2 3 4 5 6 7 8 9 10 a b a a d d a b d a

11 12 13 14 15 16 17 18 19 20 b c d c b d b d a d

21 22 23 24 25 a b d c b