Demonstrating System Reliability by the Sequential Prob-ability Ratio Test

T h e S e q u e n t i a l P robab i l i t y R a t i o Tes t is p r e sen t ed as a p r ac t i ca l s t a t i s t i c a l a p p r o a c h t o d e m o n s t r a t i n g t h e re l iab i l i ty r e q u i r e m e n t s of rocke t sy s t ems a n d s u b s y s t e m s . I n t h i s t e s t , t h e s a m p l e size is n o t p r e d e t e r m i n e d b u t , r a t h e r , t h e t e s t i n g is c o n t i n u e d a n d t h e r e su l t s ana lyzed af ter e ach s y s t e m is t e s t ed , u n t i l t h e r e su l t s a r e sufficient t o i n d i c a t e a dec is ion . T h e m a i n a d v a n t a g e s of t h i s p r o cedu re a r e (a) a general ly sma l l e r s a m p l e size t h a n t h a t r equ i red by o t h e r s t a t i s t i c a l p rocedu re s , (b) all ca l cu la t i o n s can be d o n e pr io r t o t e s t i n g a n d t h e t e s t d a t a c a n b e recorded graphica l ly w i t h o u t a d d i t i o n a l c o m p u t a t i o n s .