“David is concerned the system will fail, he wants to add a part with reliablity .75 in parallel to the whole system. Leon says this is a bad idea since the reliablity of the system is .80, true, but putting in a .75 reliablity part can't possibly help can it?
Now Leon wants to make changes. He suggests putting a part with .98 reliabity in series with the whole system "because it can't hurt, the reliblity is much lower, just .80" David says this is a horrible idea. “
I can’t stand Leon.
https://sauropods.win/@futurebird/113602345031453617
@futurebird
In an ideal world, adding a 0.75 reliable parallel part increases the overall reliability since the probability of both failing simultaneously is (1-0.8)*(1-0.75), or 0.05. […]
@futurebird Question:
Has Leon ever compared the benefit of parallel connected Xmas lights over serial ones?
@futurebird
Okay, so "in parallel" means it's a fail-over contingency, right? Like a redundant backup?
[…]
This word problem legitimately made me mad at the guy. SO ANNOYING.
@futurebird And depending on the system you really can't assume that P(failure) is independent.
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