CRE

Which of the following methods will most improve the reliability of a product?

• Reducing confidence levels
• Reducing variation
• Increasing sample size
• Increasing test time

Which of the following methods can be used to quantitatively identify items that are risk critical

• Design review
• Fault-tree analysis
• Concurent engineering
• Human reliability analysis

At the design stage of a product, the first safety focus should be on which of the following?

• Regulatory requirements
• Production tools
• Controls and equipment
• End-user applications

Which of the following statements is true about response surface methods?

• They can eliminate day-to-day variations in a manufacturing environment
• They are more efficient than two-level factorial design techniques
• They do not require technical considerations to implement the method
• They determine how an output is affected by a set of variables over a specified region

Which of the following assumptions is true about degradation?

• It is inherent and irreversible
• It is inherent and reversible
• It is unacceptable and irreversible
• It is unacceptable and reversible

A parts-count reliability prediction is calculated by summing only the

• parts failure rates
• number of parts in the system
• variances of the part failure rates
• parts failure rates with application stress

A part has a constant hazard rate. If preventive maintenance is used, the part’s failure probability will be affected in which of the following ways?

• It will increase
• It will decrease to a fixed value greater than zero
• It will decrease to zero
• It will remain the same

The use of experimental design techniques early in the process development stage generally results in

• increased personnel and product costs
• increased product development time
• decreased variability around target requirements
• decreased start-up process yields

A qualification test is planned to establish whether a unit meets required minimum mean time between failures (MTBF). Which of the following tools can be used to estimate the chance that the unit will pass the test even if its true MTBF is below the required level?

• Operating characteristic curve
• Block diagram
• Fault tree
• Transition state matrix

The reliability block diagram of a system is shown in the following figure with component reliability noted in each block.

• 0.67
• 0.726
• 0.804
• 0.82