|
The Gumbel...
[math]\displaystyle{ f(T)={ \frac{\beta }{\eta }}\left( {\frac{T}{\eta }}\right) ^{\beta -1}e^{-\left( { \frac{T}{\eta }}\right) ^{\beta }} \,\! }[/math]
Beta is the shape parameter or slope. Values less than one incicate a decreasing failure rate, greater then one an increasing failure rate, and when one a constant failure rate. Eta is the scale parameter, or characteristic life. Eta represents the time by which 63.2% of the units fail.
[math]\displaystyle{ \beta= }[/math] shape parameter (or slope).
|
