Crow-AMSAA Discrete Model Example

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

A one-shot system underwent reliability growth development testing for a total of 68 trials. Delayed corrective actions were incorporated after the 14th, 33rd and 48th trials. From trial 49 to trial 68, the configuration was not changed.


 * Configuration 1 experienced 5 failures,
 * Configuration 2 experienced 3 failures,
 * Configuration 3 experienced 4 failures and
 * Configuration 4 experienced 4 failures.

Do the following:
 * 1) Estimate the parameters of the Crow-AMSAA model using maximum likelihood estimation.
 * 2) Estimate the unreliability and reliability by configuration.

Solution  The parameter estimates for the Crow-AMSAA model using the parameter estimation for discrete data methodology yields $$\lambda = 0.5954\,\!$$ and $$\beta =0.7801\,\!$$.  The following table displays the results for probability of failure and reliability, and these results are displayed in the next two plots.

Estimated Failure Probability and Reliability by Configuration



 