3P-Weibull Rank Regression

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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.


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


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:

[math]R(t)=e^{-\left({\frac{t-\gamma }{\eta}}\right )^{\beta }}\,\![/math]

The results are [math]{\beta}\,\![/math] = 1.2, [math]{\eta}\,\![/math] = 144 and [math]{\gamma}\,\![/math] = 30

Results in Weibull++

3PW RR.png

3PW RR plot.png