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The two-parameter Weibull distribution gives R(t) = exp(-(t/eta)^beta). Beta below 1 indicates infant mortality, beta near 1 random failure and beta above 1 wear-out. The B-life at a target reliability is eta x (-ln R)^(1/beta), and mean life is eta x gamma(1 + 1/beta).
Weibull reliability
R(t) = exp(-(t / eta)^beta)
Hazard and B-life
h(t) = (beta / eta) x (t / eta)^(beta-1); B-life = eta x (-ln R)^(1/beta)
Beta near 0.5 points to manufacturing defects or installation error, beta 1 to random external causes, beta 2-4 to fatigue and abrasion, and beta above 5 to rapid wear-out or corrosion end-of-life.
By fitting failure data on a Weibull probability plot, or by maximum likelihood estimation. Suspended items that have not yet failed must be included as censored data or beta will be badly overstated.