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Reply to "Difference between FMEA and FMECA"

quote:
Now, if you are doing a Weibull analysis, we need a lot more, say 7 or 8, since 2 or 3 may get censored, and about 5 (clean) points are necessary to get 90-95% confidence.


Vee,
Have you done the maths. You need a lot more than 7 or 8 data points to get 95% confidence interval and confidence depends on the correlation of the points more so than how many there are.
And in reality, getting 7 or 8 points for analysis is hard to get given the changes in systems and operating conditions of equipment.
If you are talking 10 or 15 points you may start getting close to 95% confidence but that all depends on what distribution you select and how well the points fit that distribution.
RM
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