Weibull Distribution - Parameter Estimation
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Weibull Distribution - Parameter Estimation |
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The Weibull probability density function is where: b is the shape parameter, and In some cases, a three-parameter Weibull distribution provides a better fit than the two-parameter Weibull distribution. The difference in the two distributions is the location parameter, d, which shifts the distribution along the x-axis. By definition, there is a zero probability of failure for x<d. The location can be negative; this implies that items were failed prior to testing or entering service; examples include shipping damage, assembly damage and storage damage. The three parameter Weibull distribution is Four methods for estimating the parameters of the Weibull distribution are presented in this section: After distribution parameters have been estimated, reliability estimations and predictions are used for evaluations. The maximum likelihood estimation section explains how this can be done manually, but because of the complexity of the calculations, manual methods are not recommended. The predicting module explains how to estimate reliability using The Reliability and Maintenance Analyst software package.
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