THE ESTABLISHMENT OF TOLERANCE BOUNDS ON DATA SCATTER CAN be accomplished by using one of two available methods. One method uses standard deviations for the data distribution that can be extended to chosen probability levels (tolerance bounds) with the use of standard normal deviates, Z. The other option is to use cumulative probabilities expressed by the Weibull distribution. Because the methods differ from the standpoint of mathematical approach, the tolerance bound curves calculated will differ slightly. Since this difference is small, the choice among the two is optional.