Quality and Reliability Methods - SAS

Chapter 18 Reliability Growth 345
Additional Examples of the Reliability Growth Platform
Piecewise Weibull NHP Change Point Detection with Time in Dates Format
The file BrakeReliability.jmp, found in the Reliability subfolder, contains data on fixes to a braking system.
The Date column gives the dates when Fixes, given in the second column, were implemented. For this data,
the failure times are known. Note that the Date column must be in ascending order.
The test start time is the first entry in the Date column, 09/29/2011, and the corresponding value for Fixes
is set at 0. This is needed in order to convey the start time for testing. Had there been a non-zero value for
Fixes in this first row, the corresponding date would have been treated as the test start time, but the value of
Fixes would have been treated as 0 in the analysis.
The test termination time is given in the last row as 05/31/2012. Since the value in Fixes in the last row is
0, the test is considered to be time terminated on 5/31/2012. Had there been a non-zero value for Fixes in
this last row, the test would have been considered failure terminated.
1. Open the BrakeReliability.jmp sample data table.
2. Select Analyze > Reliability and Survival > Reliability Growth.
3. Select the Dates Format tab.
4. Select Date and click Timestamp.
5. Select Fixes and click Event Count.
6. Click OK.
7. From the red triangle menu at Reliability Growth, select Fit Model > Crow AMSAA.
The Cumulative Events plot in the Observed Data report updates to show the model (Figure 18.23). The
model does not seem to fit the data very well.