Sample Size for Weibull Distribution - Reliability

[#1]

Hello,

I have prior testing of n=22 samples, with 2 failure modes/locations. The Y of interest is lbf and ALL samples are tested to failure (no censoring). I want to use this data to determine the necessary sample size I must use for the same test to ensure that at least 95% of the selected population covered at a 95% lower confidence bound (Lower Spec limit).

The aggregate data fits a weibull distribution with a P-value of 0.175, mean of 12.716, std dev = 0.763, shape = 25.773, and scale =13.015 for the Weibull fit.

How can I determine the minimum sample size I will need (based on prior testing knowledge from above) to ensure 95/95 for a lower spec limit of 5.2 lbf?

[#2]

I am not sure if this tool will do what you want, but see the Reliability Demonstration calculator under DOE > Design Diagnostics > Sample Size and Power.

See Help > JMP Documentation Library > Design of Experiments Guide > Reliability Demonstration Calculator section for more information and a worked example.