Forum: Reliability & Maintainability Questions and Answers
Topic: Reliability & Maintainability Questions and AnswersTopic Posted by: Reliability & Maintainability Forum (firstname.lastname@example.org )
Organization: System Reliability Center
Date Posted: Mon Aug 31 12:47:36 US/Eastern 1998
Original Message:Posted by: Jeff Jackson (jackson14789 )
Date posted: Tue Nov 13 22:40:43 US/Eastern 2001
Subject: MIL-STD-471, Test Method 9, 30 Task Minimum????
I have studied MIL-STD-471A, Notice 2, "Maintainability Demonstration," Test Method 9, and want to know if anyone knows why the minimum sample size is 30 maintenance actions. Test Method 9 indicates that the procedure is based on the Central Limit Theorem. Appendix A of the document indicates that the sample of maintenance tasks must be at least four times the number of tasks for the selected test. So, the question is: Is the 30 task minimum somehow determined using the Central Limit Theorem, and if so, how?