SMALL SAMPLE ACCEPTANCE SAMPLING TABLES USING B10 RELIABLE LIFE AND B10 HAZARD RATE CRITERIA BASED ON THE WEIBULL DISTRIBUTION.

Acceptance criteria are established for B sub 10 reliable life and B sub 10 hazard instantaneous failure rate, assuming that a Weibull failure time distribution with shape parameter 0.6 or beta or 2.0 applies. B sub 10 reliable life is the time at which 90 of all items are expected to be still in operation, and B sub 10 hazard rate is the number of failures per unit - time hours, cycles, etc expected at B sub 10 life. Acceptance sampling plans based on the binomial probability distribution have been developed, for each criterion, using sample sizes of 2 or n or 50, and acceptance numbers of 0 or c or n-1, c or 8, to assure, with minimum confidence of 90 andor 95 the acceptance of lots for which the survival probability is 90 or more, at some specified time, t. Comparisons between B sub 10 reliable life and B 10 hazard rate indicate that either may be used with equal facility as acceptance sampling criteria. However, B sub 10 hazard rate estimated would be most appropriate for establishing correction factors to compare basic environmental test results, with results obtained under other than basic conditions. Author