"One-Shot" Device Reliability Tables

The tables available from this web site provide the user with a quick method of approximating:

  • The samples size required to achieve a desired confidence level given an expected or allowable number of failures.
  • The confidence level given that the allowable number of failures and sample size.
  • The allowable number of failures given the confidence level and the sample size.

There are five tables relating to the proportion defective values of: 0.01, 0.05, 0.10, 0.15, 0.20. Feel free to access any of these tables by selecting one of the following:

Proportion Defective (p) = 0.01

Proportion Defective (p) = 0.05

Proportion Defective (p) = 0.10

Proportion Defective (p) = 0.15

Proportion Defective (p) = 0.20

How to use the Tables:

Select the table for p=0.10

The plan is to test 45 units and allow no failures as the criterion of success. Go to row of the table with"0" under the column "Number of Failures" and read across to the right to the last column. The value is 45. One would be 99% confident that zero failures in a test sample of 45 items indicate that the population is no more than 10% defective. If two failures were allowed, you would go to the left column and find the value of 2. A sample size of 45 items lies between 80% and 90% Confidence Level columns. By interpolation, the Confidence level that is population is 10% defective or less is approximately 83%.