What is reliability demonstration testing and how are sample sizes determined?

Reliability demonstration testing proves reliability targets are met with statistical confidence. Sample sizes are determined using test-to-failure distributions (Weibull), target reliability level (e.g., R90), confidence level (typically 90%), and acceleration factors. Zero-failure testing uses the relationship that testing n samples to target life without failure demonstrates reliability R at confidence C where (1-R)^n = 1-C. More samples or longer tests provide higher confidence. Planning uses reliability growth curves and Bayesian methods incorporating prior knowledge. Results support warranty decisions and quality gates.