07 Exercises

Module 4 Estimation of Reliability Metrics

Lesson M04-07

Text: Section

Participant Guide: Module 4 pages 43 & 44

Duration: 24 minutes

Exercises

Here is a chance to practice reliability estimation with censored data.  You also are asked to explore how making an additional assumption (regarding the shape parameter) affects the precision of the estimates.  A second exercise asks you to compare two groups by analyzing them together.

Exercises

1. 20 switches were put on a rig test. 15 units failed and 5 were right censored (Data is found in Dataset_2.MTW)

a) Using the best fitting (Weibull) distribution:

i. Generate and interpret a plot of the failure (hazard) rate

ii. Estimate the time at which the reliability drops to 0.95

iii. Provide the 95% lower confidence bound for the above estimate

b) If we assume that b is known (at its estimated value), how does the lower 95% confidence bound on the above estimate change?

2. The diaphragm material was changed to try and improve the Pump Reliability. Compare the reliability of the two materials (Data is found in Dataset_4.MTW)

Specifically:

a) Use Distribution Fitting by Design to find a reasonable distribution to model each set of data

b) Generate a Reliability Curve by Design

c) Does there appear to be statistically significant difference in the reliability performance

Here are the exercise files mentioned:

Dataset_2.MTW

Dataset_4.MTW