The destructive degradation model can be expressed as follows:
where:
• g(Y) is the transformed Y variable
• F is the selected probability distribution
• μ is the location parameter, defined by h
• h is a function that relates the transformed Time variable and the explanatory variable X
• σ is the scale parameter of the distribution
• f(Time) is the transformed Time variable
• X is an optional explanatory variable
The standardized residuals are obtained as follows:
• For location-scale distributions, the standardized residuals are (y-μ)/σ.
• For log-location-scale distributions, the standardized residuals are (log(y)-μ)/σ.