Cochin University of Science and Techology (CUST) 2005-7th Sem B.Tech Mechanical Engineering ,, Statistical Quality Control - Question Paper
BTS (C) - VII - 05 - 070 (J)
B. Tech Degree VII Semester Examination November 2005
ME 705 (C) STATISTICAL QUALITY CONTROL
(2002 Admissions onwards)
Maximum Marks : 100
Time : 3 Hours
(Use of SQC tables is permitted)
(5)
(a)
(b)
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Discuss the terms variable and attributes. Table gives the compressive strength to the nearest gm of 50 samples of a metal spring : | ||||||||||||||||||||||||||||||||||||||||||||||||||
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(i)
(ii)
(iii)
(12)
(c)
(a)
(b) (c)
II.
(ii)
Normal distribution
Explain the following terms :
(i) Ogive curves (iii) Measures of dispersion. (3x3 = 9)
Find the probability of randomly drawing two aces in succession from an ordinary deck of 52 playing cards (i) if we sample without replacement, and (ii) if we sample with replacement. (2 x 1 Vi =3)
Discuss the following distribution :
(i) Binomial distribution (ii) Poisson distribution (2x4 = 8)
Arrange the data in groups of 0<20, 20<40, 40<60 gm and so on.
Calculate the mean, median and mode compressive strength.
Find also the range, SD, and the semi-interquartile range. Which of these measures of the dispersion would be more suitable in this case?
A die is loaded in such a way that each odd number is twice as likely to occur as each even number. If E is the event that a number greater than 3 occurs on a single toss of the die, find probability of E, i.e. P(E).
OR
(3)
(a) What is a control chart? What are the uses of control chart? (8)
III.
(b) Plot the control charts for X and R, using the following sample data on a sample size of five. Find whether the process is in control.
(12)
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OR |
Distinguish between P chart, nP chart and c, chart. Discuss some situations in which these charts are most applicable. (8)
(b) What is meant by process capability and how it is determined?
(c) The castings were inspected in order to locate defects in them. Every casting was found to contain certain number of defects as shown below. It is required to plot a c - chart and draw the conclusions.
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Casting |
1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
9 |
10 |
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No. of defects |
7 |
0 |
3 |
4 |
5 |
6 |
6 |
4 |
2 |
2 |
(7)
V. (a) Explain producers risk and consumers risk. (8)
(b) Write short notes on :
(c) In a double sampling plan N = 5000, n = 100, Q - 0, n2 = 100 and C2 = 1. Use Poissons table to compute the probability of acceptance of 1% defective lot. (6)
OR
VI. (a) Explain the term AOQL and LTPD. (6)
(c) A single sampling plan gives N = 5000, n = 100 and 0 = 2.
(i) Compute the probability of acceptance of lots with 1 % defective.
(ii) Find the AOQ value.
(5)
(5)
(10)
(8)
(12)
(10)
(10)
(10)
(10)
