The flexural strength of brittle materials has been found to follow the two-parameter Weibull distribution. This paper describes a simple method of estimating the Weibull modulus and characteristic strength that allows for the computation of confidence intervals that will contain the true values within a specifiable level of confidence. The sample size needed to meet the experimenter's precision requirements is determined. A sample of flexural strength data from the literature is used to illustrate all of the computations. The precision of the method is compared to that of the method of maximum likelihood. It is found to be inferior to maximum likelihood for estimating the Weibull modulus but quite comparable for estimating the scale parameter.
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