Test-Fix-Test Data (Failure Terminated) Reference Example

This example compares the results for test-fix-test data (failure terminated).

International Standard IEC 61164 (Reliability Growth in Product Design and Test – Statistical Test and Estimation Methods), Example 2 – Case 1, pg. 30.

The following table shows the data.

The book has the following results:


 * Beta(UnB) = 0.5594, Lambda = 1.1067


 * CL = 0.9 (two-sided confidence bounds on DMTBF)


 * DMTBFUpper = 46.7 hours


 * DMTBF = 33.5 hours


 * DMTBFLower = 24.3 hours


 * CVM = 0.041, critical value = 0.173. Since CVM < critical value can fail to reject hypothesis that the model fits the data.

In RGA, the Crow-AMSAA (NHPP) model with the maximum likelihood estimation (MLE) method was used to calculate the results.


 * The model parameters are:




 * The Cramér-von Mises goodness-of-fit test result:




 * The instantaneous MTBF and its two-sided 90% confidence intervals are shown next. The confidence bounds in the QCP are calculated using Crow Bounds methodology.