# Reliability of subsystems, including Weibull

Discussion in 'Capability - Process, Machine, Gage …' started by Cleoppa, Mar 24, 2018.

1. ### CleoppaNew Member

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Hello!

My husband is studying for the ASQ CQE exam. He is stumped on the question below, from the ASQ sample test. He was able to figure out the Exponential Life subsystems, but can't find the formula to determine the Weibull. Forgive me if I'm writing this wrong. He's the quality expert... I'm the Google expert!

Question:
A series system contains three subsystems with the following distributions.

Subsystem | Distribution
1 | Exponential life; MTBF = 10,000 hours
2 | Weibull distribution; θ = 12,000 hours... β = 0.42
3 | Exponential life; MTBF = 25,000 hours

If the system is operated for 5,000 hours, what is its reliability?

A 0.249
B 0.417
C 0.501
D 0.606

The correct answer being A. And if it displays differently on different computers, θ = theta; β = beta

Thank you very much!

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