II. A. 2. c. Expectation
II. Probability and Statistics for Reliability
A. Basic concepts
2. Basic probability concepts (Apply)
Use basic probability concepts (e.g., independence, mutually exclusive, conditional probability) and compute their values.
This lesson takes a close look at expectation – a key statistics concept.
Additional References
Expectation and Moment Generating Functions (article)
Quick Quiz
II. A. 2. b. Laws and Counting
II. Probability and Statistics for Reliability
A. Basic concepts
2. Basic probability concepts (Apply)
Use basic probability concepts (e.g., independence, mutually exclusive, conditional probability) and compute their values.
This lesson takes a close look at a few probability laws and quickly counting approaches.
Additional References
Chebychev Inequalities (article)
Markov Inequalities (article)
Permutations and Combinations (article)
Quick Quiz
II. A. 2. a. Probability
II. Probability and Statistics for Reliability
A. Basic concepts
2. Basic probability concepts (Apply)
Use basic probability concepts (e.g., independence, mutually exclusive, conditional probability) and compute their values.
This lesson takes a close look at a few basic probability concepts.
Additional References
Top Tips for Probability Analysis (article)
Why do statistical based testing? (article)
Expectation and Moment Generating Functions (article)
Quick Quiz
II. A. 2. Basic Probability Concepts
II. A. I. d. Measures of Dispersion
II. Probability and Statistics for Reliability
A. Basic concepts
1. Statistical terms (Apply)
Define and use terms such as population, parameter, statistic, sample, the central limit theorem, etc., and compute their values.
This lesson takes a close look at various measures of variation within the data.
Additional References
Variance (article)
Statistical Terms about Variation (article)
Quick Quiz
1-41. Laboratory tests of a new dental amalgam have yielded the following proportions of a critical compound: 41.2, 42.1, 44.7, and 41.9 ppm. Calculate the sample standard deviation.
(A) 1.327
(B) 1.443
(C) 1.533
(D) 1.666
(C) 1.533
The key element here is the calculation is for a sample, not a population. Thus be sure your calculator is providing the sample standard deviation result, based on this formula
$$ s=\sqrt{\frac{\sum\limits_{i=1}^{n}{{{\left( {{X}_{i}}-\bar{X} \right)}^{2}}}}{n-1}}$$
and not the formula for the population standard deviation.
$$ s=\sqrt{\frac{\sum\limits_{i=1}^{n}{{{\left( {{X}_{i}}-\bar{X} \right)}^{2}}}}{n}}$$
The difference of dividing by n or n-1 does make a difference for small sample. At about n = 30 there is little difference in the results.
II. A. I. c. Central Limit Theorem
II. Probability and Statistics for Reliability
A. Basic concepts
1. Statistical terms (Apply)
Define and use terms such as population, parameter, statistic, sample, the central limit theorem, etc., and compute their values.
This lesson takes a close look at a fundamental concept in statistics.
Additional References
Central Limit Theorem (article)
Quick Quiz
II. A. I. b. Measures of Central Tendency
II. Probability and Statistics for Reliability
A. Basic concepts
1. Statistical terms (Apply)
Define and use terms such as population, parameter, statistic, sample, the central limit theorem, etc., and compute their values.
This lesson takes a close look at how we determine the middle or most often.
Additional References
The Mean, Median, and Mode (article)
Quick Quiz
II. A. I. a. Basic Statistical Terms
II. Probability and Statistics for Reliability
A. Basic concepts
1. Statistical terms (Apply)
Define and use terms such as population, parameter, statistic, sample, the central limit theorem, etc., and compute their values.
This lesson takes a close look at common statistical language.
Additional References
Statistical Terms (article)
Terms Glossary (downloads)
Quick Quiz
1-35. Identify the correct statement about probability distributions.
(A) The median is used to measure the central tendency.
(B) The variance is used to measure the central tendency.
(C) The third moment about the mean is used to measure the kurtosis.
(D) The fourth moment about the mean is used to measure the skewness.
(A) The median is used to measure the central tendency.
Mean, median and mode are measures of central tendency.
Variance is a measure of variability. Skewness is the third moment and kurtosis is the fourth moment. BTW the mean is the first moment and variance is the second moment.
II. A. I. Statistical Terms
Probability and Statistics for Reliability Introduction
II. Probability and Statistics for Reliability
I. C. 3. System Safety
I. Reliability Management
C. Ethics, safety, and liability
3. System safety (Analyze)
Identify safety-related issues by analyzing customer feedback, design data, field data, and other information. Use risk management tools (e.g., hazard analysis, FMEA, FTA, risk matrix) to identify and prioritize safety concerns, and identify steps that will minimize the misuse of products and processes.
When a product or system fails it may increase the risk of harm (safety incidents). Likewise as systems age or degrade. The tools reliability engineers use to identify and reduce reliability risks are value to identify and eliminate or mitigate safety risks.
Additional References
MIL-STD-882E System Safety 11 May 2012 (pdf)
3 Steps NRTL use for product safety (article)
Required Case History for Reliability Engineers (article)
Quick Quiz
1-123. Which of the following is not a system-safety analytical technique?
(A) hazard analyses
(B) design readiness reviews
(C) fault tree analyses
(D) logic diagram analysis
(B) design readiness reviews
While important as part of the design process, readiness reviews do not specifically focus on system safety.
1-124. A sample of a chocolate bar is tested for the presence of peanuts (a potential allergen). Identify the only possible valid statement of the results.
(A) A “positive” result means that, given the state of the technology, no peanuts can be detected.
(B) A “negative” result means that, given the state of the technology, no peanuts can be detected.
(C) Levels above one part per billion are to be rejected.
(D) A gram of peanuts is permissible.
(B) A “negative” result means that, given the state of the technology, no peanuts can be detected.
Testing includes the capability of the measurement system including measurement error. A test that does not find evidence is only valid to the limits of the measurement capability.
1-125. There are numerous reasons to assess human factors in product safety planning. Which is not one of them?
(A) to allocate the proper balance between humans and machine
(B) to address the limitations of human beings
(C) to ascertain the user hardware interaction
(D) to accelerate material property test results
(D) to accelerate material property test results
The testing of materials may provide information concerning product safety, yet is not a human factors element thus not necessary for an assessment of human factors for safety planning.
1-126. Identify which of the following is not a way of eliminating a hazard?
(A) performing a contingency analysis
(B) performing a fault-tree analysis
(C) performing a FMEA
(D) performing a procedure analysis
(A) performing a contingency analysis
The key word here is “contingency” which implies the failure has occurs and the analysis is for a backup or work around process.
1-130. Identify the Incorrect statement concerning preliminary hazard analysis.
(A) Preliminary hazard analysis is best accomplished with actual customer complaint data of the product.
(B) Preliminary hazard analysis is normally conducted at a time when there is little design detail.
(C) Preliminary hazard analysis entails a review of safety problems prior to production.
(D) Preliminary hazard analysis can be used to identify the principal hazards when the product is in the conceptions phase.
(A) Preliminary hazard analysis is best accomplished with actual customer complaint data of the product.
The key word is “preliminary” which implies early or first analysis. Using customer complaint information implies the product is produced and shipped to customer before the analysis occurs. In general the purpose of a hazard analysis is to avoid providing a product to customers that posse a potential hazard.
1-145. Hazard severity categories are used to provide a measure of the seriousness of an event in the area of risk assessment. How would a system failure causing major environmental damage be classified?
(A) catastrophic
(B) critical
(C) marginal
(D) negligible
(B) critical
Hazard severity categories, originally defined in MIL-STD-1629A Procedures for Performing a Failure Mode, Effects and Criticality Analysis (canceled in 1998) and currently defined in MIl-STD 882D, Standard Practice for System Safety, February 10, 2008, p. 18. define the terms as follows:
Catastrophic — Could result in death, permanent total disability, loss exceeding $1M, or irreversible severe environmental damage that violates law or regulation.
Critical — Could result in permanent partial disability, injuries or occupational illness that may result in hospitalization of at least three personnel, loss exceeding $200K but less then $1M, or reversible environmental damage causing a violation of law or regulation.
Marginal — Could result in injury or occupational illness resulting in one or more lost work days, loss exceeding $10k but less then $200k, or mitigatible environmental damage without violation of law or regulation where restoration activities can be accomplished.
Negligible — Could result in injury or illness not resulting in a lost work day, loss exceeding $2k but less then $10k, or minimal environmental damage not violating law or regulation.
Catastrophic uses the term severe, Critical uses reversible, Marginal uses mitigatible, and Negligible uses minimal. Major is less then severe and has more impact than minimal. Then for me it’s a judgment call if major corresponds with Critical or Marginal.
1-147. Near the end of the design stage, what should a safety risk assessment be based on?
I. cost impact
II. hazard probability
III. hazard severity
IV. risk impact
(A) I only
(B) I and IV only
(C) II and III only
(D) II, III, and IV only
(D) II, III, and IV only
Risk assessment in general is working to identify hazards that include loss of life, accidents, or injuries; equipment, property or environmental damage. While a program may consider financial risks, it not part of a safety risk assessment.
- C. 2
1-149. All companies need to keep formal records in case of product lawsuits. Under what legal rule can company records be subpoenaed?
(A) discovery
(B) due care
(C) negligence
(D) warranty
(A) discovery
discovery:
the entire efforts of a party to a lawsuit and his/her/its attorneys to obtain information before trial through demands for production of documents, depositions of parties and potential witnesses, written interrogatories (questions and answers written under oath), written requests for admissions of fact, examination of the scene and the petitions and motions employed to enforce discovery rights. The theory of broad rights of discovery is that all parties will go to trial with as much knowledge as possible and that neither party should be able to keep secrets from the other (except for constitutional protection against self-incrimination). Often much of the fight between the two sides in a suit takes place during the discovery period. (directly from http://dictionary.law.com/default.aspx?selected=530 on May 31, 2016)
I. C. 2. Roles and Responsibilities
I. Reliability Management
C. Ethics, safety, and liability
2. Roles and responsibilities (Understand)
Describe the roles and responsibilities of a reliability engineer in relation to product safety and liability.
There are a lot of people involved creating product or manufacturing line. Some have more responsibility then others. Reliability engineers who deal with failures have unique obligations concerning product safety and liability.
Additional References
Reliability Role and Safety and Liability (article)
SOR 042 Reliability and Senior Management (podcast)
Quick Quiz
1-129. Company XYZ has manufactured a poor product that has led to the filing of a product liability lawsuit. Who is held ultimately responsible in such a lawsuit?
(A) XYZ’s president or CEO
(D) XYZ’s sales manager
(B) XYZ’s manufacturing manager
(C) XYZ’s reliability engineer
(A) XYZ’s president or CEO
The legal responsibility of an organization’s output is the person with the legal authority and responsibility to oversee, manage and approve any output.
1-148. Identify which of the following is not a major management product safety responsibility.
(A) promoting employee safety through education and training
(B) establishing a mechanism to segregate and dispose of any nonconforming product
(C) formulating a documented product safety policy
(D) ensuring that the company complies with all product safety standards and liability laws
(A) promoting employee safety through education and training
Employee safety, while important is not a product safety.
I. C. 1. Ethical Issues
I. Reliability Management
C. Ethics, safety, and liability
1. Ethical issues (Evaluate)
Identify appropriate ethical behaviors and responsibilities of a reliability engineer in relation to product safety and liability.
As with other professional fields, holders of an ASQ certification are bound by the ASQ Code of Ethics.
Additional References
Ethics and Your Work as a Reliability Engineer (article)
Quick Quiz
1-144. Wadjet, an experienced engineer working for Draconian Enterprises, has authored a book on reliability principles in her spare time. Draconian has decided to implement a reliability training program and asks her advice and she is considering recommending that her book be used. What professional action should she immediately take?
(A) Recommend another book to avoid the appearance of impropriety.
(B) Recommend her own book if in her best judgment it is the best.
(C) Inform her employer of her business connection to the book.
(D) If the book is widely available and her royalty is modest, she need take no other action.
(C) Inform her employer of her business connection to the book.
Here’s an except from the ASQ Code of Ethics (assessed 29 May 2016 at http://asq.org/about-asq/who-we-are/ethics.html)
Article 5 – Act as faithful agents or trustees and avoid conflict of interest and the appearance of conflicts of interest.
It is the conflict or appearance of a conflict of interest that is the issue. If the only reason to recommend her book is the profit that she would receive it is a conflict of interest. The employer may or not be all right with that particular arrangement, so informing them of the situation is appropriate. In this case, by not informing the other party it at a minimum appears that she is withholding information pertinent to the selection of a book for the training program.
One way to avoid the issue is to not make the recommendation. The book may well be the right one for the program and deserves consideration. By informing her employer all parties have the same information concerning the business connection to the book.
