Test for Fix Effectiveness

For reliability growth data analysis only.

The Test for Fix Effectiveness window allows you to apply Dr. Crow's "Statistical Test for Effectiveness of Corrective Actions" test for an applicable data set. This test helps you to determine whether the fixes applied during or at the end of a phase have effectively reduced a system's failure intensity.

The utility is available for:

• Any of the multi-phase data types (as long as the parameters have been calculated and the data set contains at least two phases).
• Any data sheet that has been analyzed with the Change of Slope calculation option.

To access the window, choose Growth Data > Crow Extended > Test for Fix Effectiveness.

If you are working with a multi-phase data sheet, use the Phase 1 and Phase 2 drop-down lists to choose the two phases you want to compare. If you are working with a Change of Slope analysis, Segment 1 is the data before the specified Break Point, while Segment 2 is the data after.

Specify the Significance Level (a decimal between 0 and 1) and click Test. The utility gives two results:

• The first result compares the average failure intensities of the two phases (or segments). If the average failure intensity during the second is less than during the first (at the specified significance level), the utility displays "Passed." If not, it displays "Failed."
• The second result compares the average failure intensity during the second phase (or segment) with the instantaneous failure intensity at the end of the first. If the average failure intensity during the second is less than the instantaneous failure intensity at the end of the first (at the specified significance level), the utility displays "Passed." If not, it displays "Failed."

Click the Report button to see a more detailed summary of the analysis in the Results window. This includes the failure intensities that are calculated for both phases.