How are the points on the probability plot determined in Weibull++?
Weibull++ 5.0 uses median ranks to calculate the points for the plot. Weibull++ 6 and 7 use median ranks or Kaplan-Meier estimates. For a more detailed discussion of the use of median ranks for plotting, see ReliaSoft’s Life Data Analysis Reference on the following topics. The reference is also available in an online version on weibull.com.