Probit regression examines the relationship between a binomial response and a continuous stress predictor variable. To determine whether or not the stressor has a statistically significant impact on the outcome (survival or failure) of your unit you need to do the following:
- Identify the p-value for Stress, which is the second value under P.
- Compare the p-value to your α-level: If the p-value is smaller than the α-level you have selected, the relationship between the response outcome and stress variable is statistically significantly.
A commonly used α-level is 0.05.
Variable Coef Error Z P
Constant -6.20376 1.06565 -5.82 0.000
Stress 0.0089596 0.0015615 5.74 0.000
Log-Likelihood = -38.516
For the windshield data, the p-value for Stress is 0.000, which is smaller than 0.05, indicating that the velocity of the projectile does have a significant impact on whether or not the windshield breaks.