CRE CRE Statistical Methods and Reliability Modeling 2

Question 1

Accelerated Life Testing (ALT) uses elevated stress levels primarily to accomplish which goal?

Accepted Answer

Reduce test time by inducing failures faster than normal operating conditions

Answer

ALT compresses the failure timeline so reliability predictions can be made without waiting for failures under normal conditions.

Question 2

The Arrhenius model in reliability testing is used to describe the effect of which stress variable on failure rates?

Accepted Answer

Temperature

Answer

The Arrhenius model relates reaction rate (failure rate) to temperature using the activation energy equation.

Question 3

For two components in parallel with reliabilities R1 and R2, the combined system reliability is calculated as:

Accepted Answer

1 − (1 − R1)(1 − R2)

Answer

Parallel system reliability = 1 minus the probability that both components fail simultaneously.

Question 4

In reliability testing, confidence intervals are used to:

Accepted Answer

Quantify uncertainty in reliability point estimates

Answer

Confidence intervals provide a range within which the true reliability parameter is expected to fall with a stated probability.

Question 5

The inverse power law model is commonly applied in accelerated life testing for which type of stress?

Accepted Answer

Voltage or mechanical stress

Answer

The inverse power law relates failure rate to non-thermal stresses such as voltage, pressure, or vibration.

(CRE) Certified Reliability Engineer Practice Test