A REVIEW OF THE WEIBULL DISTRIBUTION

Waloddi Weibull presented three different formulations of the distribution that bears his name, a fourth began through a printer's error, and these have been followed by other formulations. Analyses in the literature depend on the particular formulation set forth by each author, causing confusion about what works with what. This article encourages practitioners to use the Weibull distribution by furnishing historical background and parallel development of the essential formulas (cumulative distribution functions, probability density functions, hazard rates, and parameter estimates) for each of five formulations.