Sequential Data - Duane Example

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This example appears in the Reliability Growth and Repairable System Analysis Reference.

Given the sequential success/failure data in the table below, do the following:

1. Estimate the Duane parameters.
2. What is the instantaneous Reliability at the end of the test?
3. How many additional test runs with a one-sided 90% confidence level are required to meet an instantaneous Reliability goal of 80%?

Sequential Data

Run Number	Result
1	F
2	F
3	S
4	S
5	S
6	F
7	S
8	F
9	F
10	S
11	S
12	S
13	F
14	S
15	S
16	S
17	S
18	S
19	S
20	S

Solution

1. The following figure shows the data set entered into RGA along with the estimated Duane parameters.
   
2. The Reliability at the end of the test is equal to 78.22%. Note that this is the DRel that is shown in the control panel in the above figure.
3. The figure below shows the number of test runs with both one-sided confidence bounds at 90% confidence level to achieve an instantaneous Reliability of 80%. Therefore, the number of additional test runs required with a 90% confidence level is equal to [math]\displaystyle{ 42.2481-20=22.2481\approx 23\,\! }[/math] test runs.