Deck 19: Statistical Process Control and Quality Management

Question 1

A _________ chart portrays the number of defects per unit of production.

Answer 1

c-bar

Question 2

One purpose of quality control is to reduce the costs associated with producing and delivering poor quality goods and services.

Answer 2

True

Question 3

If the binomial distribution is used to develop an operating characteristic curve for an acceptance sampling plan, then the trials must be ________________.

Answer 3

independent

Question 4

Mean charts are designed to determine whether a process is in or out of control based on sample means.

Question 5

In acceptance sampling, there is one unique operating characteristic curve for a specified sampling plan.

Question 6

In acceptance sampling, usually 100% of the incoming lot is checked.

Question 7

The following are examples of attributes: the width of a cracked weld, the length of time that a relay works; the amount of water in a radiator; the diameter of a tire.

Question 8

Quality control charts indicate whether a production process is in control or out of control.

Question 9

Assignable causes are usually large in number and random in nature, and they cannot be entirely eliminated.

Question 10

Control charts can be developed for both variables and attributes.

Question 11

Pareto charts are based on the 80-20 rule, which says 80% of the factors cause 20% of the problem.

Question 12

A c-bar chart shows the percent of the production that is defective.

Question 13

If the binomial distribution is used to develop an operating characteristic curve for an acceptance sampling plan, there can be a total of _____ possible outcomes.

Question 14

In an acceptance sampling plan, the incoming lot is ___________ if the number of defective items in the sample is less than or equal to the acceptance number.

Question 15

In acceptance sampling, it is possible that an incoming lot of computer chips contains more defective chips than it should, but it is still accepted. In acceptance sampling, this probability is called _____________.

Question 16

The purpose of a statistical quality control chart is to identify when assignable causes of variation have entered the production system so that the cause may be identified and corrected.

Question 17

In acceptance sampling, if the number of defects in a sample is less or equal to the acceptance number, then the incoming lot is accepted.

Question 18

A fishbone diagram is used to determine if a process is out of control.

Question 19

There are two general types of causes of variations in manufacturing and service processes: chance and assignable causes.

Question 20

Percent defective charts, which are also known as p-charts or c-bar charts, show the percent of the production that is or is not acceptable.

Question 21

If the sample ranges fall randomly within the upper and lower control limits, then it can be assumed that the process is ___________.

Question 22

A range chart shows the variation of ____________.

Question 23

A statistical quality control chart that is out of control shows what a(n) ___________ variation.

Question 24

One of the most important concepts of statistical process control is that no two products are ________________.

Question 25

The ______ chart portrays the number of defects per unit.

Question 26

Acceptance sampling and control charts may be based on measurements with either ______________ or ___________________.

Question 27

A Pareto chart is typically skewed to the ________________.

Question 28

The concepts of statistical quality control developed in the decade of the ______.

Question 29

________ causes of variation cannot be entirely eliminated.

Question 30

The measurement of color is a(n) _____________.

Question 31

A fishbone diagram is an ________________ tool.

Question 32

The purpose of a statistical control chart that plots sample means is to __________________________.

Question 33

A Pareto chart is designed to show the ____________ in which different types of defects occur in a process.

Question 34

A Pareto chart is useful because it is based on the theory that 80% of the observations are accounted for by 20% of the ________.

Question 35

The center line of a mean chart is labeled as _______.

Question 36

A fishbone diagram starts with the definition of a problem and explores its possible ________.

Question 37

_________ variation is due to slight changes in materials or process conditions and is random in nature.

Question 38

Another name for the p-bar chart is the ______________.

Question 39

In a fishbone diagram, "dissatisfied customers" would be an _________ and "slow service" would be a _________.

Question 40

The "in control" region of a control chart is called the ____________________.

Question 41

A chart used to show the results of a Pareto analysis is a:

A) range chart.
B) bar chart.
C) control chart.
D) fishbone diagram.

Question 42

What is the process that insures that a company is producing a quality product or service?

A) Six Sigma
B) Pareto analysis
C) Fishbone chart analysis
D) Diagnostic chart

Question 43

Cappelli Inc. designs and manufactures women's apparel using material from various mills. Their acceptance sampling plan states that 20 two-inch squares of the incoming material must be carefully checked. If 3 or less squares reveal imperfections, the lot is accepted. What is the probability that an incoming lot from Blufton Mills that contains 40 percent imperfect cloth will be accepted?

A) 0
B) 0.239
C) 0.015
D) 0.0024

Question 44

The cause-and-effect chart is an example of a:

A) range chart.
B) Pareto chart.
C) control chart.
D) fishbone diagram.

Question 45

A fishbone diagram classifies potential causes into categories. What are they?

A) Chance and assignable variation
B) Methods, materials, equipment, and personnel
C) Percent defective and percent non-defective
D) Causes and effects

Question 46

The technique that tallies types of defects and their frequency is called:

A) range charts.
B) Pareto analysis.
C) control charts.
D) fishbone diagram.

Question 47

What type of variation can be reduced, or even eliminated, and is usually nonrandom in nature?

A) chance
B) external
C) assignable
D) co-variation

Question 48

Equipment failure would be an example of ____________ variation.

A) chance
B) external
C) assignable
D) standard

Question 49

Samples of 200 parts were taken every day and the number of defectives was counted. What are the upper and lower limits for the percent defective chart?

A) 0.02 and 0
B) 0.2970 and 0
C) 0.0297 and 0
D) 0.0497 and 0

Question 50

Which probability distribution is used to develop a control chart for sample means?

A) Normal distribution
B) Chi-square distribution
C) Poisson distribution
D) Binomial distribution

Question 51

Which probability distribution is used to develop an operating characteristic curve?

A) Normal distribution
B) Chi-square distribution
C) Poisson distribution
D) Binomial distribution

Question 52

What process investigates the potential causes of an outcome or effect such as poor quality?

A) SPC
B) Pareto analysis
C) Fishbone chart analysis
D) Diagnostic chart

Question 53

A sampling plan states that if 20 incoming bolts are checked and 2 or less defective bolts are discovered, the lot will be rejected. If an incoming lot is 10 percent defective, what is the probability of rejecting the lot?

A) 0
B) 1
C) 0.323
D) 0.667

Question 54

What is usually developed to evaluate a sampling plan?

A) Frequency polygon
B) Scatter diagram
C) Operating characteristic curve
D) Simple bar chart

Question 55

A sampling plan states that if 20 incoming transistors are checked and 2 or less defects are found, the lot is accepted. If an incoming lot is 10 percent defective, what is the probability of accepting the lot of transistors?

A) 0
B) 1
C) 0.677
D) 0.333

Question 56

Which probability distribution is used to develop a percent defective chart?

A) Normal distribution
B) Chi-square distribution
C) Poisson distribution
D) Binomial distribution

Question 57

A subassembly is inspected and the number of defects recorded. A new group of assemblers began work Monday morning. The number of defects per subassembly for the first 10 they produced was: 3, 2, 0, 5, 4, 6, 0, 7, 7, and 6. What are the upper and lower limits for the c-bar chart?

A) 15 and 0
B) 10 and 0
C) 1.12 and 0
D) 6 and -2

Question 58

If a company reports that its quarterly earnings will be between $100 million and $125 million depending on the consumer demand, consumer demand is an example of ________ variation.

A) chance
B) external
C) assignable
D) standard

Question 59

What chart helps to identify the relatively few factors that impact the performance of a manufacturing or service process?

A) SPC
B) Pareto analysis
C) Fishbone chart analysis
D) Diagnostic chart

Question 60

If a company reports that its quarterly earnings will be between $100 million and $125 million, the range is an example of _________ variation.

A) chance
B) external
C) assignable
D) controlled

Question 61

A new machine that fills tubes of toothpaste will be monitored using statistical process control. The following data were collected while the machine was closely monitored and under control. Each day a random sample of six tubes are weighed. Based on the data, the process mean is 6.752. What is the lower control limit for the x-bar chart rounded to three decimal places?

A) 6.816
B) 6.676
C) 6.688
D) 6.828

Question 62

A new machine is set or calibrated to fill tubes of toothpaste at precisely 6.75 ounces. Then, once the machine is running, a sample of six tubes is taken every three hours and weighed with the following results: What is the value for the lower control limit (LCL) of the range?

A) 0.00
B) 0.080
C) 0.186
D) 0.203

Question 63

A new machine is set or calibrated to fill tubes of toothpaste at precisely 6.75 ounces. Then, once the machine is running, a sample of six tubes is taken every three hours and weighed with the following results: What is X-bar for 7 pm?

A) 6.71
B) 6.72
C) 6.74
D) 6.76

Question 64

A new machine is set or calibrated to fill tubes of toothpaste at precisely 6.75 ounces. Then, once the machine is running, a sample of six tubes is taken every three hours and weighed with the following results: What is the range of the samples at 7 am?

A) 0.05
B) 0.06
C) 0.11
D) 0.12

Question 65

Control charts are used to determine if a process is:

A) in or out of control.
B) measurable.
C) fixable.
D) testable.

Question 66

A new machine is set or calibrated to fill tubes of toothpaste at precisely 6.75 ounces. Then, once the machine is running, a sample of six tubes is taken every three hours and weighed with the following results: What is the value of the upper control factor of the range?

A) 0
B) 2.115
C) 2.004
D) 3.0

Question 67

A new machine is set or calibrated to fill tubes of toothpaste at precisely 6.75 ounces. Then, once the machine is running, a sample of six tubes is taken every three hours and weighed with the following results: What is X-bar for 7 am?

A) 6.72
B) 6.74
C) 6.78
D) 6.80

Question 68

The Quality Assurance Department selected 12 samples of 100 printed circuit boards and tested them. The number of defective printed circuit boards in each sample was 3, 3, 0, 5, 1, 1, 5, 6, 6, 2, 0, and 1. What kind of control chart should be constructed to monitor the process?

A) mean chart
B) range chart
C) percent defective chart
D) c-bar chart

Question 69

A new machine is set or calibrated to fill tubes of toothpaste at precisely 6.75 ounces. Then, once the machine is running, a sample of six tubes is taken every three hours and weighed with the following results: What is the value of A₂, the control limit factor for averages?

A) 0
B) 1
C) 0.577
D) 0.483

Question 70

A new machine is set or calibrated to fill tubes of toothpaste at precisely 6.75 ounces. Then, once the machine is running, a sample of six tubes is taken every three hours and weighed with the following results: What is the upper control limit (UCL) for the mean?

A) 6.738
B) 6.999
C) 6.777
D) 7.221

Question 71

A new machine is set or calibrated to fill tubes of toothpaste at precisely 6.75 ounces. Then, once the machine is running, a sample of six tubes is taken every three hours and weighed with the following results: What is the mean range?

A) 0.000
B) 0.160
C) 0.080
D) 0.203

Question 72

A new machine is set or calibrated to fill tubes of toothpaste at precisely 6.75 ounces. Then, once the machine is running, a sample of six tubes is taken every three hours and weighed with the following results: What is the range of the samples at 4 pm?

A) 0.05
B) 0.06
C) 0.11
D) 0.12

Question 73

A new machine is set or calibrated to fill tubes of toothpaste at precisely 6.75 ounces. Then, once the machine is running, a sample of six tubes is taken every three hours and weighed with the following results: What is the value of the lower control factor of the range?

A) 0
B) 2.115
C) 2.004
D) 3.0

Question 74

The Quality Assurance Department selected a sample of 12 printed circuit boards and tested them. The number of defects in each circuit board was 3, 3, 0, 5, 1, 1, 5, 6, 6, 2, 0, and 1. What kind of control chart should be constructed to monitor the process?

A) mean chart
B) range chart
C) percent defective chart
D) c-bar chart

Question 75

If the upper and lower control limits are set at ±3 standard deviations from the mean, we would expect that:

A) 99.7% of the sample means are within the control limits.
B) 95% of the sample means are within the control limits.
C) about 68% of the sample means are within the control limits.
D) about 5% of the sample means are outside the control limits.

Question 76

In a control chart, expected variation is defined by the:

A) standard deviation.
B) standard error of the distribution.
C) upper control limits only.
D) upper and lower control limits.

Question 77

A new machine used in the production of motor mount bolts was put into operation. Five samples of size 100 were randomly selected and the number of defectives in each sample was noted. What is the lower control limit (LCL)?

A) 0%
B) -2.2%
C) 4.8%
D) 1.6%

Question 78

A new machine used in the production of motor mount bolts was put into operation. Five samples of size 100 were randomly selected and the number of defectives in each sample was noted. What is the upper control limit (UCL)?

A) 6.7%
B) 7.4%
C) 8.1%
D) 100%

Question 79

A new machine used in the production of motor mount bolts was put into operation. Five samples of size 100 were randomly selected and the number of defectives in each sample was noted. What is the average percent defective?

A) 2.0%
B) 2.3%
C) 2.6%
D) 2.9%

Question 80

The upper and lower control limits are usually set:

A) at the mean.
B) above the mean.
C) at three standard deviations from the mean.
D) at two standard deviations from the mean.