Q&A Hero

Q: Demand can be altered in aggregate planning by promotion and producing additional product using overtime.

Q: The output from aggregate planning is a detailed business plan covering the next 2 to 12 months.

Q: The assignment of work to specific machines and people are examples of aggregate planning.

Q: Aggregate planning is used to establish general levels of employment, output, and inventories over an intermediate range of time.

Q: Aggregate planners are concerned with the quality and quantity of expected demand.

Q: The goal of aggregate planning is to achieve a production plan that attempts to balance the organization's resources and meet expected demand.

Q: Aggregate planning is capacity planning that typically covers a time horizon of one to three months.

Q: The range chart (R-chart) is most likely to detect a change in: A. proportion. B. mean. C. number defective. D. variability. E. sample size.

Q: A shift in the process mean for a measured characteristic would most likely be detected by a: A. p-chart. B. x-bar chart. C. c-chart. D. R-chart. E. s-chart.

Q: A plot below the lower control limit on the range chart: (I) should be ignored since lower variation is desirable. (II) may be an indication that process variation has decreased. (III) should be investigated for assignable cause. A. I and II B. I and III C. II and III D. II only E. I, II, and III

Q: _______ variation is a variation whose cause can be identified. A. Assignable B. Controllable C. Random D. Statistical E. Theoretical

Q: The probability of concluding that assignable variation exists when only random variation is present is: (I) the probability of a Type I error. (II) known as the alpha risk. (III) highly unlikely. (IV) the sum of probabilities in the two tails of the normal distribution. A. I and II B. I and IV C. II and III D. I, II, and IV E. I, III, and IV

Q: Which of the following is not a step in the quality control process? A. Define what is to be controlled. B. Compare measurements to a standard. C. Eliminate each of the defects as they are identified. D. Take corrective action if necessary. E. Evaluate corrective action.

Q: Which of the following relationships must always be incorrect? A. Tolerances > process variability > control limits B. Process variability > tolerances > control limits C. Tolerances > control limits > process variability D. Process variability > control limits > tolerances E. Process variability < tolerances < control limits

Q: If a process is performing as it should, it is still possible to obtain observations which are outside of which limits? (I) tolerances (II) control limits (III) process variability A. I B. II C. I and II D. II and III E. I, II, and III

Q: A point which is outside of the lower control limit on an R-chart: A. is an indication that no cause of variation is present. B. should be ignored because it signifies better-than-average quality. C. should be investigated because an assignable cause of variation might be present. D. should be ignored unless another point is outside that limit. E. is impossible since the lower limit is always zero.

Q: A control chart used to monitor the number of defects per unit is the: A. p-chart. B. R-chart. C. x-bar chart. D. c-chart. E. Gantt chart.

Q: A c-chart is used for: A. means. B. ranges. C. percent defective. D. fraction defective per unit. E. number of defects per unit.

Q: A p-chart would be used to monitor: A. average shrinkage. B. dispersion in sample data. C. the fraction defective. D. the number of defects per unit. E. the range of values.

Q: A control chart used to monitor the fraction of defectives generated by a process is the: A. p-chart. B. R-chart. C. x-bar chart. D. c-chart. E. Gantt chart.

Q: A control chart used to monitor the process mean is the: A. p-chart. B. R-chart. C. x-bar chart. D. c-chart. E. Gantt chart.

Q: A time-ordered plot of representative sample statistics is called a(n): A. Gantt chart. B. simo chart. C. control chart. D. up-down matrix. E. standard deviation table.

Q: Which of the following quality control sample statistics indicates a quality characteristic that is an attribute? A. mean B. variance C. standard deviation D. range E. proportion

Q: The greater the volume of the process being targeted for inspection, the more attractive __________ inspection is. A. monitored B. controlled C. periodic D. variable E. automated

Q: The amount of inspection needed depends on __________ and __________. A. the amount of automation; the reliability of inspectors B. the quality of the supplier; the target market of the process C. the costs of inspection; the costs of passing on defective items D. where in the process the inspection occurs; the volume of the process E. the cost of the item being inspected; the use of the item being inspected

Q: Acceptance sampling, when it is used, is used: (I) before production. (II) during production. (III) after production. A. I only B. I and III only C. I and II only D. II and III only E. I, II, and III

Q: Inspection is a(n): A. prevention. B. control. C. monitoring. D. corrective. E. appraisal.

Q: The assurance that processes are performing in an acceptable manner is the focus of: A. variability analysis. B. quality assurance. C. capability assessment. D. quality control. E. acceptance sampling.

Q: Quality control tools are not really used to fix quality so much as they are used to: A. highlight when processes are not capable. B. point out when random variation is present. C. alert when corrective action is needed. D. monitor the quality of incoming shipments or outgoing finished goods. E. initiate team-building exercises.

Q: The more effective and all-encompassing a firm's quality control and continuous improvement efforts, the less that company will need to rely on: A. insourcing. B. inspection. C. outsourcing. D. acceptance sampling. E. capability assessment.

Q: Quality control, in contrast to quality assurance, is implemented: A. during production. B. by top management. C. after production. D. by self-directed teams. E. before inspection.

Q: Range control charts are used to monitor process central tendency.

Q: When a process is not centered, its capability is measured in a slightly different way. The symbol for this case is Cpk.

Q: Larger samples will require wider x-bar control limits because there is more data.

Q: The number of defective parts in a sample is an example of variable data because it will "vary" from one sample to another.

Q: Attribute data are counted, variable data are measured.

Q: Control limits are based on multiples of the process standard deviation.

Q: The best way to assure quality is to use extensive inspection and control charts.

Q: Approximately 99.7 percent of sample means will fall within plus or minus two standard deviations of the process mean if the process is under control.

Q: The sampling distribution can be assumed to be approximately normal even when the underlying process distribution is not normally distributed. TRUE

Q: The variation of a sampling distribution is tighter than the variation of the underlying process distribution.

Q: The Taguchi loss function suggests that the capability ratio can be improved by extending the spread between LCL and UCL.

Q: The primary purpose of statistical process control is to detect a defective product before it is shipped to a customer.

Q: Quality control is making sure that processes are performing in an acceptable manner.

Q: The process capability index (indicated by Cpk) can be used only when the process is centered.

Q: Cpk is useful even when the process is not centered.

Q: A run test checks a sequence of observations for randomness.

Q: Statistical process control focuses on the acceptability of process output.

Q: Run tests give managers an alternative to control charts; they are quicker and cost less.

Q: Run tests are useful in helping to identify nonrandom variations in a process.

Q: The output of a process may not conform to specifications even though the process may be statistically "in control."

Q: Patterns of data on a control chart suggest that the process may have nonrandom variation.

Q: Control limits tend to be wider for more variable processes.

Q: Control limits used on process control charts are specifications established by design or customers.

Q: Process capability compares process variability to the tolerances.

Q: Tolerances represent the control limits we use on the charts.

Q: A c-chart is used to monitor the number of defects per unit for process output.

Q: A c-chart is used to monitor the total number of defectives in the output of a process.

Q: A p-chart is used to monitor the fraction of defectives in the output of a process.

Q: Range charts and p-charts are both used for variable data.

Q: Range charts are used mainly with attribute data.

Q: An R value of zero (on a range chart) means that the process must be in control since all sample values are equal.

Q: Concluding that a process is out of control when it is not is known as a Type I error.

Q: An x-bar control chart can only be valid if the underlying population it measures is a normal distribution.

Q: If a point on a control chart falls outside one of the control limits, this suggests that the process output is nonrandom and should be investigated.

Q: A process that exhibits random variability would be judged to be out of control.

Q: The purpose of statistical process control is to ensure that historical output is random.

Q: The amount of inspection needed is governed by the costs of inspection and the expected costs of passing defective items.

Q: The amount of inspection we choose can range from no inspection at all to inspecting each item numerous times.

Q: Attributes need to be measured, whereas variable data can be counted.

Q: A lower control limit must by definition be a value less than an upper control limit.

Q: Low-cost, high-volume items often require more intensive inspection than other types of items.

Q: High-cost, low-volume items often require careful inspection since we make them so infrequently.

Q: Processes that are in control eliminate variations.

Q: The optimum level of inspection minimizes the sum of inspection costs and the cost of passing defectives.

Q: The optimum level of inspection occurs when we catch at least 98.6 percent of the defects.

Q: Statistical process control is the measurement of rejects in the final product.

Q: Approving the effort that occurs during the production process is known as acceptance sampling.

Q: A stent for use in coronary surgery requires a special coating. Specifications for this coating call for it to be at least 0.05 millimeters but no more than 0.15 millimeters. Assuming that the process mean of 0.09 cannot be changed, what process standard deviation would be required for this process to be considered capable (assuming that a capable process must have a capability index of at least 1.3)?

Q: Given the following process control data for a quality attribute (three samples of size 400 each): If the process proportion of defectives is unknown, using .10 alpha risk control limits, do any of the sample proportions indicate an out-of-control process proportion of defectives?