R90C90 type analysis

[mahlman]

[Originally Posted: 11/1/00--Transferred by ReliaSoft Moderator]

I have been asked to provide an R90/C90 plot. I am not versed in this area of analyses. Could someone please help out? I would like to know if this is an acronym for something that may be listed in the help files? As well, would it be possible for someone to provide detailed instructions on how to do this using the smith-weibull software?

[S. Nath]

[Originally Posted: 11/1/00--Transferred by ReliaSoft Administrator]

RrrCcc specification means a reliability target(lower bound) or rr with a level of confidence of cc. R90C90 is 90% lower bound of reliability with confidence level of 90%.

[Dr. Dave Olwell]

[Originally Posted: 11/1/00--Transferred by ReliaSoft Moderator]

I agree that R90C90 means 90% reliablity with 90% confidence, but that is a point in time, usually.

What I imagine you want is a reliability versus time plot with the one sided lower confidence bound included. If you are using it to estimate warranty times, you want Type I confidence bounds (the horizonatal ones).

I'd be glad to help you develop such a plot on Weibull++, but I don't use WinSmith (and I am surprised you asked for help on it from the ReliaSoft board! You, sir, are an optimist!)

Best wishes,

Dr. Dave