1. Describe the three phases of the life history curve.
2. A manufacturer of car seat belt latching mechanisms is interested in testing the reliability of the metal clip and latch system that serves to attach the seat belts securely around a passenger. Would this require cycle-dependent testing or time-dependent testing? Briefly state why.
3. Reliability programs have been used to prolong the lives of tornado sirens that signal the approach of bad weather. Describe a tornado siren in terms of the definition of reliability.
4. Determine the failure rate for a 90-hour test of 12 items where 2 items fail at 45 and 72 hours, respectively. What is the mean life of the product?
5. A power station has installed 10 new generators to provide electricity for a local metropolitan area. In the past year (8,776 hours), two of those generators have failed, one at 2,460 hours and one at 5,962 hours. It took five days, working 24 hours a day, to repair each generator. Using one year as the test period, what is the mean time between failure for these generators? Given the repair information, what is the availability of all 10 generators?
6. Since nothing discourages return visits more than long lines, ski resorts have to move people up the mountain quickly. The list systems they use need to be reliable. This past summer, one resort tested the reliability of their 20 different lifts by using a time-terminated test. The test ran for 100 hours of continuous operation. During the test, four lifts broke down, at 40, 65, 80, and 89 hours. Calculate the mean life for the lifts. If it takes an average of 12 hours to repair a lift, calculate the availability of the lifts.
7. Why is a parallel system more reliable than a system in series?
8. There are four specific types of quality costs. Clearly define two of them. Give an example of each kind of quality cost you have defined.
9. How do the four types of quality costs vary in relation to each other?
10. What should a quality-cost program emphasize?
11. What are the benefits of having, finding, or determining quality costs?
12. Describe the relationship among prevention costs, appraisal costs, and failure costs. Where should a company's efforts be focused? Why?
13. For each of the following activities, identify whether the costs incurred should be allocated to the prevention, appraisal, failure (internal, external), or intangible costs category:
a. Customer inquires about incorrect billing statement.
b. Maintenance technician is unable to gain access to customer's premises during a service call because the service is not being performed when scheduled and no one notified the customer.
c. Workers check/test their work before allowing it to leave their work area.
d. Management carries out a quality systems audit.
e. The accounts department is having difficulty obtaining monthly figures from the production department.
f. A customer's purchase breaks because of inadequate training in the use of the item and must be replaced.
g. Management must deal with written complaints from a customer about continuous poor service.
h. A technician keeps an appointment after driving across town to pick up equipment from an outside supplier upon finding it out of stock in his own warehouse.
i. An instruction manual and set of procedures are developed for maintaining a new piece of equipment.
j. The company conducts a survey of customer requirements.