Download PTU (I.K.Gujral Punjab Technical University (IKGPTU)) B-Tech (Bachelor of Technology) (IE)- Industrial Engineering 2020 December 4th Sem 61018 Statistical Quality Control Previous Question Paper
Total No. of Pages : 03
Total No. of Questions : 16
B.Tech. (Ind. Engg. & Mgt.) (TQM) (Sem.?4)
STATISTICAL QUALITY CONTROL
Subject Code : IEM-403
M.Code : 61018
Time : 3 Hrs. Max. Marks : 40
INST RUCT IONS T O CANDIDAT ES :
1 .
Attempt EIGHT out of T EN questions from SECT ION - A ca rrying T WO marks
each.
2 .
Attempt a ny FOUR out of SIX q ues tions from SECT ION -B ca rrying SIX mark s
each.
SECTION-A
Answer briefly :
1)
It has been argued that the definition of product quality as `fitness for intended purpose' is
more likely to lead to commercial success than is a definition such as `conformance to
specification'. Discuss the implications of these alternative definitions for the Quality
Control function within a manufacturing enterprise.
2)
Explain the classification of defects on basis of seriousness.
3)
Distinguish between the use of the mean, median, and mode in quality control applications.
4)
What are the advantages and disadvantages of using variables rather than attributes in
control charts?
5)
Describe the use of the Pareto concept in the selection of characteristics for control charts.
6)
Discuss Taguchi quadratic loss function.
7)
Explain the concept of process capability and when it should be estimated. What is its
impact on nonconformance?
8)
What condition must exist prior to calculating the process capability?
9)
Explain the difference between average sample number and average total inspection. State
any assumptions made.
10) Distinguish between producer's risk and consumer's risk.
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SECTION-B
11) Explain the objectives of inspection in the manufacturing organizations. Discuss the need
for inspection and testing. Also, explain various types of inspection procedures adopted in
manufacturing organizations.
12) Explain the difference between natural tolerance limits and specification limits. How does a
process capability index incorporate both of them? What assumptions are made in
constructing the natural tolerance limits?
13) Consider a single sampling plan with a lot size of 1500, sample size of 150, and acceptance
number of 3. Construct the OC curve. If the acceptable quality level is 0.05%
nonconforming and the limiting quality level is 6% nonconforming, describe the protection
offered by the plan at these quality levels.
14) The roughness of the ground surface of a component cannot exceed 0.02 units. A random
sample of components ground by a surface-grinding machine yielded the following
estimates : Mean roughness = 0.01. Standard deviation = 0.003. Computer the Cp index
of this process and estimate the proportion of defectives expected to be generated by the
process, assuming that the surface roughness measurements follow normal distribution.
15) The thickness of a printed circuit board is an important quality parameter. Data on board
thickness (in inches) are given in Table below for 25 samples of three boards each.
a) Set up x and R control charts. Is the process in statistical control?
b) Estimate the process standard deviation.
c) What are the limits that you would expect to contain nearly all the process
measurements?
Printed Circuit Board Thickness
Sample
Sample
x
x
Number
1
x2
x3
Number
1
x2
x3
1
0.0629
0.0636
0.0640
2
14
0.0645
0.0640
0.0631
0.0630
0.0631
0.0622
3
15
0.0619
0.0644
0.0632
0.0628
0.0631
0.0633
4
16
0.0631
0.0627
0.0630
0.0634
0.0630
0.0631
5
17
0.0616
0.0623
0.0631
0.0619
0.0628
0.0630
6
18
0.0630
0.0630
0.0626
0.0613
0.0629
0.0634
7
19
0.0636
0.0631
0.0629
0.0630
0.0639
0.0625
8
20
0.0640
0.0635
0.0629
0.0628
0.0627
0.0622
9
21
0.0628
0.0625
0.0616
0.0623
0.0626
0.0633
10
22
0.0615
0.0625
0.0619
0.0631
0.0631
0.0633
11
23
0.0630
0.0632
0.0630
0.0635
0.0630
0.0638
12
24
0.0635
0.0629
0.0635
0.0623
0.0630
0.0630
13
25
0.0623
0.0629
0.0630
0.0635
0.0631
0.0630
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16. The number of customers who are not satisfied with the service provided in a retail store is
found for 20 samples of size 100 and shown in Table. Construct a control chart for the
proportion of dissatisfied customers. Revise the control limits, assuming special causes for
points outside the control limits.
TABLE
Sample
Number of Dissatisfied Sample Number of Dissatisfied
Customers
Customers
1
2
11
5
2
5
12
4
3
4
13
2
4
3
14
5
5
4
15
3
6
2
16
12
7
3
17
3
8
2
18
2
9
4
19
5
10
11
20
2
NOTE : Disclosure of Identity by writing Mobile No. or Making of passing request on any
page of Answer Sheet will lead to UMC against the Student.
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This post was last modified on 13 February 2021