# 3P-Weibull Rank Regression

 3P-Weibull Rank Regression

This example validates the calculations for 3-parameter Weibull with rank regression in Weibull++ standard folios.

Reference Case

Table 6.3 on page 292 in the book Reliability Engineering Handbook Vol 1 by Dr. Kececioglu, Prentice-Hall, 1991.

Data

Num. in State State F or S Time to Failure
1 F 46
1 F 64
1 F 83
1 F 105
1 F 123
1 F 150
4 S 200

Result

In the book, the results are obtained by visually fitting a straight line to the median rank at each failure point. The reliability function for a 3P-Weibull distribution is:

$R(t)=e^{-\left({\frac{t-\gamma }{\eta}}\right )^{\beta }}\,\!$

The results are ${\beta}\,\!$ = 1.2, ${\eta}\,\!$ = 144 and ${\gamma}\,\!$ = 30

Results in Weibull++