Prepare for the Actual ASQ Certification CRE Exam Practice Materials Collection [Q226-Q249]

Q226. A mission profile is:
I. Time-phased.
II. A summary of events and environments.
III. All activities from initiation to completion of a mission.
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Q227. What is the general use of an R chart?
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Q228. Looking at systems in terms of (1) a series-parallel functional configuration, (2) using a truth table approach, or (3) performing a Monte-Carlo simulation are techniques for:
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Q229. A random sample of 100 bars of aluminum shows a tensile strength mean of 30,000 psi and a standard deviation of 3,000 psi. On the basis of this sample, what is the 95 percent confidence interval for the average tensile strength?
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Q230. Failure occur on a system at 75, 79, 83, 85 hours. Assuming normality, one sided and unbiased the lower tolerance limit for 95% reliability with 90% confidence for this sample is:
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Q231. To achieve 96 percent reliability at a 90 percent confidence level:
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Q232. The reliability of a complex system can BEST be improved by:
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Q233. Which of the following is NOT a degradation mechanism?
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Q234. What is the MOST vital information to know about a system in order to perform a hardware FMECA?
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Q235. If a company monitors field reliability using both 6 and 12 month MTBF moving average, a comparison of the average will generally show that the 12 month moving averages Response:

Q236. Typical statistical distributions or confidence limits can be determined for accelerated tests. In the case of a step-stress test, the proper estimated distribution would be which of the following?
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Q237. A full factorial design of experiments has four factors. The first factor has two levels, the second factor has three levels, the third factor has two levels, and the final factor has four levels. How many runs are required for this analysis?
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Q238. A randomly failing component is tested to r failures, and n observations are made. Degrees of freedom for calculating confidence limits on the mean should be:
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Q239. One method of evaluating the design reliability is to analyze the design assuming the worst case. Which of the following techniques is NOT applicable for worst case analysis?
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Q240. What is meant by “derating”?
I. The technique of using a part, component, or equipment under stress conditions considerably below rated values, to achieve a “reliability margin” in design.
II. The technique of using a part, component, or equipment under normal conditions to achieve a reliable product design.
III. The technique of using a part, component, or equipment below stress conditions to achieve a reliable product design.
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Q241. Which of the following provides the maximum benefit of parts standardization?
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Q242. For a high compression aircraft air conditioning system, the MTBF is 100 hours. This mean life is allocated for four serial units comprising the total system. The unit failure rates are then weighted as follows:
w 1 = 0.1250 w 3 = 0.1875
w 2 = 0.2500 w 4 = 0.4375
Based upon the above data, indicate which of the following is the correct calculation for one of the units.
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Q243. The flat portion of the bathtub curve is a region of chance failures; therefore, for the reliability equation shown below:
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Q244. Which of the following is NOT an appropriate element in the definition of availability?
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Q245. Preventive maintenance time includes:
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Q246. Given the sample data: 5, 15, 10, 7, 20. What is the unbiased estimator of the sample variance?
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Q247. For the ANOVA Table below, what is the Fcal statistic?

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Q248. The following fault tree diagram was developed by a team.

The probability are as follow:
A1 = 0.90 B1 = 0.90 C1 = 0.80
A2 = 0.80 B3 = 0.80 C2 = 0.70
A4 = 0.70
The likelihood that the system fault will occur is
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Q249. Preliminary hazard analysis:
I. Is a review of safety problems prior to production.
II. Is normally done at a time when there is little design detail.
III. Can be used to identify the principal hazards when the product is first conceived.
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