Determinação do tamanho de lote mínimo em amostragem aleatória para materiais, empregando a distribuição de Weibull (Determination of minimum sample size from randomic numbers for materials, applying Weibull distribution)

Regarding brittle materials, where some properties can be represented by Weibull distribution, the necessity of a new method of minimum sample be presented must be highlighted. Thus, a model has been built as baseline from a method already applied to normal distribution supported by statistical tools. Applying Cochran methodology, a new model was built, starting from numbers truly random, under normal distribution and using variation coefficients by four given numerical ranges faking the brittle materials randomly dispersion. Such numbers packs were deployed into new smaller distributions. Ensuring normal and distribution compliance. Adopting specific criteria, numerical tables are outcome, which encloses coefficient of variation, numerical ranges and Weibull parameters with minimum batch number as a function of the maximum number of batches.