UNIT 2

QUESTIONS

- What is frequency distribution? Explain in brief histogram and frequency polygon.
- Discuss normal distribution curve used in statisticial analysis.
- State the importance of normal distribution curve
- Explain the measure of central tendency.
- Explain the terms :

- Mean
- Median
- Mode
- Variance
- Standard Deviation
- Characteristics of population

6. Define Mechanical reliability

7. Explain the difference between mechanical reliability and factor of safety

8. Write the Relation between Reliability and quality.

9. Show that for two populations x and y, the standard deviation of the resultant population, both for addition and subtraction is given by

10. Three cylindrical components, each with a length of 30mm, are to be assembled to give a total length of 90 mm. All individual components have the same standard deviation and their natural and design tolerances are equal. Specify the tolerances for individual components.

11. It is observed from a sample of 1000 bearing bushes that the inner diameter is normally distributed with mean of 50.015mm and standard deviation of 0.08mm. If the inner diameter specified on drawing is 50.01 ≠0.1mm, calculate the number of bushes likely to be from that sample. Refer Table area under normal curves from 0 to Z.

12. Transmission shafts are manufactured on a machining center. The designer has specified the diameter as 40 ≠ 0.04mm. The natural tolerance is normally Distributed with mean of 40mm. If only 34% of total manufactured shafts are found to be acceptable, determine the standard deviation of this manufacturing process.Refer Table area under normal curves from 0 to Z.