Reliability analysis

Failure times and right-censored times (suspensions) go in one list. Beta and eta are estimated by maximum likelihood, where a suspension counts as a unit known to have survived to its time. Confidence bounds are approximate Wald bounds from the curvature of the likelihood, taken on a log scale; with few failures they are rough. B10 is the time at which the model puts 10% failed. Rank regression on adjusted median ranks is available as an exploratory probability plot, without bounds.

The Arrhenius factor converts stress time to use time for a stated activation energy, assuming one temperature-driven failure mechanism. It is not an accelerated-life model, which needs failures at two or more stress levels. A zero-failure demonstration n = ln(1−confidence) / ln(reliability) is the success-run plan, and it assumes a test of one life.