Risk Factors

Hazard Ratio

Std. Err.

z

P > |z|

Insuff. Lub. Oil

1.301

0.172

1.990

0.047

Impact

1.619

0.223

3.500

0.000

Stress corrosion cracking

2.328

0.405

4.860

0.000

Model fitting information

No. of Obs. = 299

Log-likelihood = −1159.466

LR Chi²(3) = 44.09

Prob > Chi² = 0.0000