
Lognormal, Weibull & Heavy-Tailed Cauchy Distributions
Compare lognormal, Weibull and Cauchy models for positive measurements, reliability lifetimes and heavy-tailed errors. Prerequisites: normal probabilities, logarithms, continuous densities and moments. Work from parameter interpretation to survival calculations, conditional lifetime reasoning and model selection. Explanations distinguish log-scale summaries from original-scale summaries and examine when conventional moments and averaging arguments fail. Cover: Photo by ThisIsEngineering on Pexels. Further reading: [PDF and Common Statistics](https://www.itl.nist.gov/div898/handbook/eda/section3/eda3669.htm), [PDF, CDF, survival and hazard](https://www.itl.nist.gov/div898/handbook/eda/section3/eda3668.htm), [PDF, CDF and Common Statistics](https://www.itl.nist.gov/div898/handbook/eda/section3/eda3663.htm).
Oct 23, 2026










