Reliability Data - Lloyd-Lipow Model

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This example appears in the Reliability growth reference.

Given the reliability data in the table below, do the following:

1. Fit the Lloyd-Lipow model to the data using least squares analysis.
2. Plot the Lloyd-Lipow reliability with 90% 2-sided confidence bounds.
3. How many months of testing are required to achieve a reliability goal of 90%?
4. What is the attainable reliability if the maximum duration of testing is 30 months?

Reliability Data

Time (months)	Reliability (%)
1	33.35
2	42.50
3	58.02
4	68.50
5	74.20
6	80.00
7	82.30
8	89.50
9	91.00
10	92.10

Solution

1. The next figure displays the estimated parameters.
   
2. The figure below displays Reliability vs. Time plot with 90% 2-sided confidence bounds.
   
3. The next figure shows the number of months of testing required to achieve a reliability goal of 90%.
   
4. The figure below displays the reliability achieved after 30 months of testing.