# Design of Machine Tools MCQ with Answer - Part 2.

1. Histogram is

a. A set of rectangles

b. A line graph of class frequency plotted against class marks

c. A bell shaped smooth curve

d. None of the above

Ans: a

2. Frequency polygon is

a. A set of rectangles

b.A line graph of class frequency plotted against class marks

c. A bell shaped smooth curve

d. None of the above

Ans: b

3. Central tendency of population is

a. Spread of data or extend to which the observations are scattered

b. Mid point of distribution where most of the data cluster

c. Concentration of data at either low or high end

d. Distribution with sharp peak

Ans: b

4. Dispersion of population is

a. Spread of data or extend to which the observations are scattered

b. Mid point of distribution where most of the data cluster

c. Concentration of data at either low or high end

d. Distribution with sharp peak

Ans: a

5. Skewness of population is

a. Spread of data or extend to which the observations are scattered

b. Mid point of distribution where most of the data cluster

c. Concentration of data at either low or high end

d. Measure of sharp peak

Ans: c

6. Kurtosis of population is

a. Spread of data or extend to which the observations are scattered

b. Mid point of distribution where most of the data cluster

c. Concentration of data at either low or high end

d. Measure of sharp peak

Ans: d

7. Central tendency of population is measured in units of

a. Standard deviation

b. Arithmetic mean

c. Standard variable

d. Square of standard de

Ans: b

8. Dispersion of population is measured in units of

a. Standard deviation

b.Arithmetic mean

c.Geometric mean

d. Square of standard deviation

Ans: a

9. Standard variable is

a. Square of standard deviation

b.Arithmetic mean

c. Root mean square deviation from the mean

d. Deviation from mean in units of standard deviation

Ans: d

10. Standard deviation is

a. Square of standard variable

b.Arithmetic mean

c. Root mean square deviation from the mean

d. Deviation from mean in units of standard deviation

Ans: c

11. The area below normal curve from (Z = - ∞) to (Z = + ∞) is

a.1

b.0.6827

c. 0.9545

d. 0.9973

where Z is standard variable

Ans: a

12. The area below normal curve from (Z = - 1) to (Z = + 1) is

a. 1

b. 0.6827

c. 0.9545

d. 0.9973

where Z is standard variable

Ans: b

13. The area below normal curve from (Z = - 2) to (Z = + 2) is

a.1

b. 0.6827

c. 0.9545

d. 0.9973

where Z is standard variable

Ans: c

14. The area below normal curve from (Z = - 3) to (Z = + 3) is

a.1

b. 0.6827

c. 0.9545

d. 0.9973

where Z is standard variable

Ans: d

15. When two populations with means μ X and μ Y are added, the mean of resultant

population is given by,

a. ( μ X + μ Y )

b. ( μ X − μ Y )

c. ( μ X μ Y )

d. ( μ X / μ Y )

Ans: a

16. When population Y with means μ Y is subtracted from population X with mean μ X , the

mean of resultant population is given by,

a. ( μ X + μ Y )

b. ( μ X − μ Y )

c. ( μ X μ Y )

d. ( μ X / μ Y )

Ans: b

17. When two populations with means μ X and μ Y are multiplied, the mean of resultant

population is given by,

a. ( μ X + μ Y )

b. ( μ X − μ Y )

c. ( μ X μ Y )

d. ( μ X / μ Y )

Ans: c

18. When population X with mean μ X , is divided by population Y with mean μ Y , the

mean of resultant population is given by,

a. ( μ X + μ Y )

b. ( μ X − μ Y )

c. ( μ X μ Y )

d. ( μ X / μ Y )

Ans: d

19. When two populations X and Y are added, the standard deviation of resultant population

is given by,

a. ( σ ˆ X + σ ˆ Y )

b. ( σ ˆ 2X + σ ˆ 2Y )

c. √( σ ˆ 2X + σ ˆ 2Y )

d. √( σ ˆ 2X − σ ˆ 2Y )

Ans: c

20. When population Y is subtracted from population X, the standard deviation of resultant

population is given by,

a. ( σ ˆ X + σ ˆ Y )

b. ( σ ˆ 2X + σ ˆ 2Y )

c. ( σ ˆ 2X + σ ˆ 2Y )

d. ( σ ˆ 2X − σ ˆ 2Y )

Ans: c

21. The resultant population is normally distributed,

a. When populations of two normally distributed random variables are added

b. When populations of two normally distributed random variables are subtracted

c. When populations of two normally distributed random variables are multiplied

d. Any one of above

Ans: d

22. In statistically controlled system,

a. Variations due to assignable causes are corrected

b. Variations due to chance causes are corrected

c. Variations due to assignable and chance causes are corrected

d. None of these

Ans: a

23. There is no rejection of components when

a. Design tolerance is equal to ( ± 3 σ ˆ ) and the process is centered

b. Design tolerance is slightly more than ( ± 3 σ ˆ )

c. Design tolerance is ( ± 4 σ ˆ )

d. Any one of above

Ans: d

24. The reliability of ball bearing selected from manufacture’s catalogue is

(a) 90%

(b) 50%

(c) 99%

(d) More than 90%

Ans: a

25. What is the standard deviation of clearance population for the diameter of shaft and hole

assembly specified below?

Shaft diameter = 30 ± 0.15

Hole diameter = 30.5 ± 0.25

a.0.097 mm

b.0.059 mm

c.0.036 mm

d.0.390 mm

Ans: b

26. Which of the following curves have the mean value equal to zero in the graph of

frequency vs random variable?

a.Normal distribution curve

b.Standard normal distribution curve

c.Both a. and b.

d.None of the above

Ans: b

27. What is the relation between standard deviation(σ) and arithmetic mean (μ) to determine

coefficient of variation (C)?

a.C = σ + μ

b.C = σ – μ

c.C = σ / μ

d.C = σ x μ

Ans: c

28. Assignable causes are caused due to changes in _________

a. Manufacturing process

b. Material

c. Inspection process

d. All of the above

Ans: d

29. If a relief valve has reliability of 0.989, how many failures are expected in testing 1000

such relief valves?

a. 111

b.100

c.10

d.11

Ans: d

30. Failure rate for safety valve working for 400 hours is 3 x 10–6 failures/hour. What is the

reliability of safety valve?

a.0.998

b.0.989

c.0.888

d.0.899

Ans: a

31. What is meant by hazard rate?

a.Number of failures per unit time per number of items when exposed for same time

b.Probability of test specimen fails between time t1and t1+ dt1which survives for time t1

c.Both a. and b.

d.None of the above

Ans: c

32. What causes infant mortality in mechanical equipments?

a.Design errors

b.Manufacturing defects

c.Installation defects

d.All of the above

Ans: d

33. A plain carbon steel has mean yield strength of 300 N/mm2 and standard deviation of 50 N/mm2 What is the mean and standard deviation of margin of safety, if mean tensile stress of 250 N/mm2 and standard deviation of 65 N/mm2 acts on it?

a. 23.45 N/mm2

, 50 N/mm2

b. 50 N/mm2

, 82 N/mm2

c. 82 N/mm2

, 7.07 N/mm2

d. 7.07 N/mm2

, 50 N/mm2

Ans: b

34. What is meant by mean time to failure (MTTF)?

a. Mean time between two successive failure components

b. Maximum time between two successive failure components

c. Sum of survival time for number of components divided by number of failures

d. Sum of number of failures divided by survival time for number of components

Ans: c

35. The variation in an apperantly identical componat are due to---

a. Variation in material

b. Variation in manufaturing process

c. Variation in workmanship

d. All of the above

Ans: d

36. It is practically imposible to produce exactly identical component of ---

a. Same geometrical properties

b. Same material properties

c. Same functional properties

d. All of the above

Ans: d

37. Assigenable cause do not occur at random but are the result of changes in the material,

manufacturing process, inpection process.

a. True

b. False

c. Insufficiant data

d. None of the above

Ans: a

38. In a frequncy distribution , there are different measures of central value or central

tendancy. Choose correct option.

a. Arithematic mean

b. Median

c. Mode

d. All of the above

Ans: d

39. The dispression or variation or spread of a frequncy distribution is measured in number

of units like--

a. Standard deviation

b. Number of units

c. Quartile Deviation

d. All of the above

Ans: d

40. Coefficient of variation is defined as----

a. Ratio of the standard deviation to the arithematic mean

b. Ratio of mean deviation to the arithematic mean

c. Ratio of quartile deviation to the arthematic mean

d. None of the above

Ans: a

41. In standard normal distribution curve the mean is equal to---

a. 1

b. 0

c. -1

d. 2

Ans: b

42. In standard normal distribution curve the standard deviation is equal to---

a. 1

b. 2

c. -1

d. 3

Ans: a

43. In standard normal distribution curve the area under curve is always equal to---

a. 2

b. 3

c. 4

d. 1

Ans: d

44. In normal distribution curve the standard deviation is any value of ---

a. Ψ

b. ˆб

c. μ

d. z

Ans: b

45. In normal distribution curve the mean is only value of ---

a. Ψ

b. б

c. μ

d. z

Ans: c

46. In normal distribution curve the random variable is--

a. X

b. б

c. μ

d. z

Ans: a

47. In normal distribution curve the standard variable is--

a. X

b. б

c. μ

d. z

Ans: d

48. Distribution of population under normal distribution curve population within band

μ + 3ˆб equal to

a. 99.73 %

b. 95.45 %

c. 68.27 %

d. 78.25 %

Ans: a

49. Distribution of population under normal distribution curve population within band

μ + 2ˆб equal to

a. 99.73 %

b. 95.45 %

c. 68.27 %

d. 78.25 %

Ans: b

50. The mode is / are obeservation/ s that occurs--------

a. Most frequntly

b. Not frequntly

c. Insufficiant data

d. None of the above

Ans: a

51. When the design tolerance is grater than the natural tolerance there is---

a. No rejection

b. Rejection

c. Insufficiant data

d. None of the above

Ans: a

52. When the design tolerance is equal to the natural tolerance there is---

a. No rejection

b. Rejection

c. Insufficiant data

d. None of the above

Ans: a

53. When the design tolerance is less than the natural tolerance there is---

a. No rejection

b. Rejection

c. Insufficiant data

d. None of the above

Ans: b

54. Reliability it is usually denoted by R and is expressed by a number within the range---

a. 0 ≤ R ≤ 1

b. -1 ≤ R ≤ 0

c. 1 ≤ R ≤ 2

d. 2 ≤ R ≤ 3

Ans: a

55. Reliability is defined as the probability that a component , system or device will perform

without failure for a specified period of time under the specified operating conditions.

a. Incorrect

b. Correct

c. Insufficiant data

d. None of the above

Ans: b