CET Follow-Up & Survival Analysis 2

Question 1

What does the survival function S(t) represent in reliability analysis?

Accepted Answer

The probability that a component survives beyond time t

Answer

S(t) gives the probability that a component or system has not failed by time t.

Question 2

If a component has a constant failure rate λ = 0.002 failures/hour, what is its MTBF?

Accepted Answer

500 hours

Answer

MTBF = 1/λ = 1/0.002 = 500 hours for a constant (exponential) failure rate.

Question 3

In the 'bathtub curve,' which region is characterized by a decreasing failure rate?

Accepted Answer

Infant mortality period

Answer

The infant mortality (early failure) region shows a decreasing failure rate as weak units are screened out.

Question 4

The hazard function h(t) in reliability analysis represents:

Accepted Answer

The instantaneous failure rate given that the item has survived to time t

Answer

h(t) is the conditional instantaneous failure rate for units that have survived up to time t.

Question 5

What is 'right censoring' in a survival analysis context?

Accepted Answer

The study ending before all items have failed

Answer

Right censoring occurs when the observation period ends before a unit fails, so the exact failure time is unknown but known to be beyond the observation time.

(CET) Certified Electronics Technician Practice Test

(CET) Certified Electronics Technician Practice Test

CET Follow-Up & Survival Analysis 2