Deck 19: Statistical Process Control and Quality Management

Question 1

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

Answer 1

0.0497 and 0

Question 2

What is usually developed to evaluate a sampling plan?

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

Answer 2

Operating characteristic curve

Question 3

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

Answer 3

False

Question 4

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

Question 5

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

Question 6

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

Question 7

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

Question 8

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 9

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 10

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

Question 11

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 12

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

Question 13

These 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 14

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 15

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

Question 16

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

Question 17

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

Question 18

Control charts can be developed for both variables and attributes.

Question 19

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

Question 20

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

Question 21

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 22

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 23

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

Question 24

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 25

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

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

Question 26

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 27

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 28

Control charts are used to determine if a process is ________.

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

Question 29

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 30

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 31

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 32

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 nondefective
D)Causes and effects

Question 33

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 34

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

A)Chance
B)External
C)Assignable
D)Covariation

Question 35

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 36

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)0.016
D)0.0024

Question 37

The cause-and-effect chart is an example of a ________.

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

Question 38

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 39

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 40

Equipment failure would be an example of ________ variation.

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

Question 41

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 42

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 43

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 44

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)6.779
D)7.221

Question 45

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 46

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 47

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 48

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 LCL?

A)0%
B)−2.2%
C)4.8%
D)1.6%

Question 49

Random samples of four items are selected from a manufacturing process at regular intervals and a certain quality characteristic is measured. After 25 samples,ΣX = 15,350 and ΣR = 411.4. To construct a mean chart,what is the value for R-bar used to compute the limits?

A)411.4
B)614
C)16.46
D)102.88

Question 50

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 51

Random samples of four items are selected from a manufacturing process at regular intervals,and a certain quality characteristic is measured. After 25 samples,ΣX = 15,350 and ΣR = 411.4. To construct a mean chart,what is the value for the centerline?

A)15,350
B)614
C)411.4
D)3837.5

Question 52

Random samples of four items are selected from a manufacturing process at regular intervals and a certain quality characteristic is measured. After 25 samples,ΣX = 15,350 and ΣR = 411.4. What is the sample size?

A)4
B)25
C)100
D)20

Question 53

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 54

Random samples of four items are selected from a manufacturing process at regular intervals and a certain quality characteristic is measured. After 25 samples, = 15,350 and = 411.4. How many samples were collected?

A)4
B)25
C)100
D)20

Question 55

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 56

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 UCL?

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

Question 57

Random samples of four items are selected from a manufacturing process at regular intervals and a certain quality characteristic is measured. After 25 samples,ΣX = 15,350 and ΣR = 411.4. To construct a mean chart,what is the upper control limit for the mean?

A)614.00
B)411.4
C)626.00
D)3837.5

Question 58

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 59

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 60

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 61

A quality control chart is used to monitor the customer wait time at a local call center. Sample means of five times are averaged and plotted over time. The last 50 sample means are randomly distributed between the upper and lower control limits. The process is ________.

A)out of control
B)in control
C)improving
D)showing assignable variation

Question 62

A quality control chart is used to monitor the customer wait time at a local call center. Sample means of five times are averaged and plotted over time. Over the last hundred sample means,no sample means were outside a control limit. The chart shows ________.

A)chance variation
B)standard variation
C)assignable variation
D)total variation

Question 63

A large restaurant contracts with a local laundry to wash white napkins. The laundry returns the napkins in bundles of 100 napkins. The restaurant randomly samples 10 napkins from each bundle to make sure that the napkins are clean with no stains or other defects. By sampling only 10 of the napkins,the restaurant may conclude that all of the napkins are clean and use the bundle,even when the napkins are actually dirty and should not be used. This sampling risk is called ________.

A)producer's risk
B)uncertainty
C)consumer's risk
D)inspection risk

Question 64

A curve that graphs the percent defective versus the probability of accepting that percent defective is referred to as ________.

A)a percent defective chart
B)a range chart
C)an operating characteristic curve or OC curve
D)a c-bar chart

Question 65

Consider a company that wishes to verify that an incoming product meets the stipulated requirements by screening the products using a statistical sampling plan. If the sample inspection reveals that a lot was accepted even though it had more defects than it should,this is referred to as ________.

A)a Type I error
B)producer's risk
C)consumer's risk
D)a sampling error

Question 66

Random samples of four items are selected from a manufacturing process at regular intervals and a certain quality characteristic is measured. After 25 samples,ΣX = 15,350 and ΣR = 411.4 The measurement of quality is based on ________.

A)an attribute
B)a variable
C)a scale
D)a chart

Question 67

Consider a situation where the lower control limit of a percent defective chart is negative. It must be that ________.

A)the absolute value of the negative LCL must be taken to arrive at a positive value
B)an error was made in computing the LCL because negative values are impossible
C)the process is out of control and must be redesigned
D)the lower limit is set to zero

Question 68

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. The measurement of quality is based on ________.

A)an attribute
B)a variable
C)a scale
D)a chart

Question 69

Random samples of four items are selected from a manufacturing process at regular intervals and a certain quality characteristic is measured. After 25 samples,ΣX = 15,350 and ΣR = 411.4. To construct a mean chart,what is the LCL for the mean?

A)602.00
B)411.40
C)625.67
D)0.00

Question 70

A large restaurant contracts with a local laundry to wash white napkins. The laundry returns the napkins in bundles of 100 napkins. The restaurant uses a sampling plan to make a decision to use the bundle of napkins or return the bundle to the laundry. The sampling plan uses a sample size of ten with a "number of rejects allowed" of one. If the number of dirty napkins in a sample of ten is two,what decision is made?

A)The sample of ten is returned to the laundry.
B)The bundle is returned to the laundry.
C)The bundle is accepted and used.
D)The good napkins from the sample are kept.

Question 71

A diagnostic chart used to identify sources of variation,where the number and types of defects are tallied,is referred to as a(n)________.

A)fishbone diagram
B)X-bar chart
C)Pareto chart
D)process control chart

Question 72

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. The measurement of quality is based on ________.

A)an attribute
B)a variable
C)a scale
D)a chart

Question 73

A large restaurant contracts with a local laundry to wash white napkins. The laundry returns the napkins in bundles of 100 napkins. The restaurant randomly samples 10 napkins to make sure that the napkins are clean with no stains or other defects. The restaurant is using a method called ________.

A)statistical process control
B)fishbone analysis
C)Pareto analysis
D)acceptance sampling

Question 74

Random samples of four items are selected from a manufacturing process at regular intervals and a certain quality characteristic is measured. After 25 samples,ΣX = 15,350 and ΣR = 411.4. To construct a range chart,what is the UCL for the range?

A)37.553
B)411.400
C)0.000
D)102.850

Question 75

A quality control chart is used to monitor the customer wait time at a local call center. Sample means of five times are averaged and plotted over time. Over the last hundred sample means,one sample mean was outside a control limit. The process is ________.

A)out of control
B)in control
C)highly variable
D)showing an assignable cause

Question 76

A quality control chart is used to monitor the customer wait time at a local call center. Sample means of five times are averaged and plotted over time. The last five sample means show a trend of increasing sample means. The process is ________.

A)out of control
B)in control
C)improving
D)showing chance variation

Question 77

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: The measurement of quality is based on ________.

A)an attribute
B)a variable
C)a scale
D)a chart

Question 78

In acceptance sampling,the risk of accepting a poor-quality lot is known as ________.

A)consumer's risk
B)producer's risk
C)a Type I error
D)none of these answers is correct

Question 79

A quality control chart is used to monitor the customer wait time at a local call center. Sample means of five times are averaged and plotted over time. The last five sample means show a trend of decreasing sample means. The process is ________.

A)out of control
B)in control
C)improving
D)showing chance variation

Question 80

Random samples of four items are selected from a manufacturing process at regular intervals and a certain quality characteristic is measured. After 25 samples,ΣX = 15,350 and ΣR = 411.4. To construct a range chart,what is the LCL for the range?

A)602.004
B)411.400
C)625.666
D)0.000