If the fit of the line on a Weibull probability plot is not good, the initial analysis parameters should be altered and new probability plots generated until an acceptable fit is found. Once this occurs, results from the Weibull analysis can be used to accurately predict the trends in the data set and estimate future failures. As time goes on, Weibull probability plots can be based on larger failure samples. Although the Weibull parameters, β and η, will be different for each Weibull probability plot, they will gradually stabilise and approach the true Weibull. With the appropriate fit, however, the important engineering inferences about B-21 life and the failure forecasts do not change significantly as the sample size increases. With complete samples (no suspensions), β and η oscillate around the true unknown value.