CMRP Reliability Data Analysis and Statistics 2

Question 1

What are the two primary parameters of a two-parameter Weibull distribution?

Accepted Answer

Shape (β) and scale (η)

Answer

Mean and standard deviation

Answer

Location and dispersion

Answer

Failure rate and repair rate

Question 2

In Weibull analysis, what does a shape parameter (β) value of less than 1 indicate about the failure pattern?

Accepted Answer

Infant mortality failures with a decreasing failure rate

Answer

Wear-out failures with increasing failure rate

Answer

Random failures at a constant rate

Answer

Bimodal failures from two competing failure modes

Question 3

When the Weibull shape parameter (β) equals exactly 1, the Weibull distribution reduces to which distribution?

Accepted Answer

Exponential distribution

Answer

Normal distribution

Answer

Lognormal distribution

Answer

Gamma distribution

Question 4

What does the eta (η) parameter represent in a Weibull distribution?

Accepted Answer

The characteristic life at which 63.2% of units have failed

Answer

The minimum guaranteed life before any failure

Answer

The median time to failure

Answer

The maximum expected service life

Question 5

A Weibull shape parameter (β) of approximately 3.5 is often associated with which type of failures?

Accepted Answer

Wear-out failures approximating a normal distribution

Answer

Random electronic failures

Answer

Infant mortality defects

Answer

Corrosion-induced sudden failures

Question 6

Which graphical technique is most commonly used to estimate Weibull parameters from failure data?

Accepted Answer

Weibull probability paper with median rank plotting

Answer

Scatter plot with linear regression

Answer

Histogram with normal curve overlay

Answer

P-chart with control limits

Question 7

The lognormal distribution is best suited to model which reliability scenario?

Accepted Answer

Repair times and failures due to fatigue or corrosion crack growth

Answer

Electronic components with a constant failure rate

Answer

Catastrophic failures in safety-critical systems

Answer

Infant mortality defects caught during burn-in