Professor Blake OPM 160 Name__________________________
Spring 2009
FINAL, Version A
Use a Scantron Form No. 886-E to record your choice of the best answer to each of the following questions. You have the full period to answer the questions.
The following questions are worth three (3) points each.
1. The Six Sigma concept redefines quality performance in terms of defects per million opportunities.
a) True
b) False
2. The improvement methodologies proposed by Deming, Juran, and Crosby have common themes which are shared in the Six Sigma approach.
a) True
b) False
3. Sampling techniques are designed for manufacturing operations and not for service operations.
a) True
b) False
4. A sample is a subset of a population.
a) True
b) False
5. It is advocated in Six Sigma that design features and characteristics be dominated by engineering considerations rather than by customer requirements.
a) True
b) False
6. The process capability index Cp equals 1.0 when the design tolerance equals the natural variation of the process.
a) True
b) False
7. A process capability index of 1.0 is more desirable than an index of 2.0.
a) True
b) False
8. Six Sigma represents a quality level of at most
a) 1.5 defects per million opportunities.
b) 2.0 defects per million opportunities.
c) 3.4 defects per million opportunities.
d) 4.5 defects per million opportunities.
9. Focusing on how to maintain improvements occurs in which DMAIC phase?
a) Measure
b) Analyze
c) Improve
d) Control
10. The operative measure of quality in Six Sigma terminology is
a) defects per unit.
b) defects per thousand units.
c) defects per ten thousand opportunities.
d) defects per million opportunities.
11. A subset of items selected from a population is called a
a) sample.
b) statistic.
c) census.
d) parameter.
12. Statistical thinking is a philosophy of learning and action based on all of the following principles except
a) All work occurs in a system of interconnected processes.
b) Variation exists in all processes.
c) All variation can be traced to human error.
d) Understanding and reducing variation are keys to success.
13. The first step in building the House of Quality is to
a) identify customer requirements.
b) evaluate the competition.
c) identify technical requirements.
d) identify selling points.
14. A bottling machine fills soft drink bottles with an average of 12.000 ounces with a standard deviation of 0.002 ounces. Determine the process capability index, Cp, if the design specification for the fill weight of the bottles is 12.000 ounces plus or minus 0.015 ounces.
a) 1.25
b) 2.5
c) 7.5
d) 12.5
The following problems/questions are worth fifteen (15) points each,
1. The specification limits for the weight of a part is 23.1 ± 2.4 grams. A manager collected a random sample of 40 units of the part from a metal stamping process. The sample average is 22.825 grams and the sample standard deviation is 1.375 grams.
a. What is the value of Cp for this product?
b. Is the metal stamping machine capable?
Since Cp is less than 1.0, the machine is not capable.
2. Define statistical process control (SPC) and discuss its advantages.
Statistical process control is a methodology using control charts for assisting operators, supervisors, and managers to monitor the output from a process to identify and eliminate special causes of variation. The advantages of using it are a) that it can help to reduce scrap and rework, increase productivity, determine process capability, predict yield from a process, and provide evidence that processes are in control to customers who may ask for it.
3. What does one look for in interpreting control charts? Explain the possible causes of different out-of-control indicators.
The characteristics that one looks for in interpreting control charts are those that indicate whether or not the process is remaining in control, or whether assignable causes have crept into throw the process out of control. These might be detected through using the rules of thumb of: 1) one point outside of a control limit; 2) two out of three consecutive points in the outer one-third region; 3) four out of five points in the outer two-thirds region, or 4) eight consecutive points on the same side of the centerline. Such out-of-control indicators may be traced to causes such as: one-time events (calculating error, power surges); sudden shifts in process average (new operator, inspector, or machine setting); cycles (day vs. night shifts, gauge variations, seasonal effects); trends (tool wear, operator fatigue, improving operator skills); hugging the centerline (taking samples from several machines, miscalculation of control limits).
4. Some of the key processes associated with business activities for a typical company include sales and marketing, supply chain management, managing information technology, and managing human resources. What type of six sigma projects might be considered in order to improve each of these activities?
Sales and marketing projects
Perceived product value
Overall customer satisfaction
Sales force effectiveness
Complaint reduction
Gains and losses of customers
Customer awards/recognitions
Supply chain management projects
Internal supplier quality measurements
Defect levels
Response time
Customer ratings of prod/service performance
Managing information technology projects
Internal information technology quality measurements
Defect levels
Response time
Customer ratings of service performance
Improvement of procurement process for software and hardware
Human resource projects
Root cause analysis and reduction of absenteeism
Root cause analysis and reduction of turnover
Measurement and improvement of employee satisfaction
Measurement and improvement of training effectiveness
Grievance reduction
Suggestion system improvement
Safety improvement
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