Multiple choice questions - quality control

 

A Quality Analyst wants to construct a sample mean chart for controlling a packaging process. He knows from past experience that whenever this process is under control, package weight is normally distributed with a mean of twenty ounces and a standard deviation of two ounces. Each day last week, he randomly selected four packages and weighed each:

Day WEIGHT (ounces)

Monday 23 22 23 24

Tuesday 23 21 19 21

Wednesday 20 19 20 21

Thursday 18 19 20 19

Friday 18 20 22 20

If he uses upper and lower control limits of 22 and 18 ounces, on what day(s), if any, does this process appear to be out of control?

Question 1 options:

Monday

Tuesday

Monday and Tuesday

Monday, Tuesday, and Thursday

none

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Question 2 (1.67 points)

A Quality Analyst wants to construct a control chart for determining whether three machines, all producing the same product, are under control with regard to a particular quality variable. Accordingly, he sampled four units of output from each machine, with the following results:

Machine Measurements

Number1 17 15 15 17

Number2 16 25 18 25

Number3 23 24 23 22

For upper and lower control limits of 23.29 and 16.71, which machine(s), if any, appear(s) to have an out-of-control process mean?

Question 2 options:

machine Number1

machine Number2

machine Number3

all of the machines

none of the machines

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Question 3 (1.66 points)

A Quality Analyst wants to construct a control chart for determining whether three machines, all producing the same product, are under control with regard to a particular quality variable. Accordingly, he sampled four units of output from each machine, with the following results:

Machine Measurements

Number1 17 15 15 17

Number2 16 25 18 25

Number3 23 24 23 22

What is the estimate of the process mean for whenever it is under control?

Question 3 options:

16

19

20

21

23

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Question 4 (2.5 points)

Specifications for a piece of material used in the manufacture of a bed mattress require that the piece be between 52.47 and 55.53 inches. The process that produces the piece yields a mean of 54 and a standard deviation of 0.9 inches. The distribution of output is normal. What percentage of the pieces will meet the length specs?

Question 4 options:

4.45 %

91.08 %

97.85 %

95.54 %

None of the Above

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Question 5 (2.5 points)

Specifications for a piece of material used in the manufacture of a bed mattress require that the piece be between a Lower and Upper value (in inches) centered around the process mean. The process that produces the piece yields a mean of 59 and a standard deviation of 0.8 inches. The distribution of output is normal. Within what values will 85.01 percent of sample means fall, if samples of n = 5 are taken and the process is in control?

Question 5 options:

58.484 , 59.515

58.166 , 59.833

57.847 , 60.152

57.211 , 60.788

None of the Above

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Question 6 (2.5 points)

Loan Processing times are being monitored at a local company. Samples of six observations each have been taken, and the results are listed. Using Factors from Table 10.3, determine lower and upper control limits for a a mean chart

Sample Number 1 2 3 4 5

------------- 44 48 56 46 27

------------- 32 49 26 52 42

------------- 31 31 21 42 40

------------- 33 26 35 46 39

------------- 41 44 40 27 44

------------- 27 43 28 46 36

Question 6 options:

25.664 , 50.468

26.834 , 49.298

10.922 , 65.21

24.494 , 51.638

None of the Above

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Question 7 (2.5 points)

Loan Processing times are being monitored at a local company. Samples of ten observations each have been taken, and the results are listed. Using Factors from Table 10.2, determine lower and upper control limits for a a Range chart

Sample Number 1 2 3

------------- 79 81 77

------------- 72 79 83

------------- 74 70 82

------------- 82 81 84

------------- 69 64 80

------------- 82 76 71

------------- 82 85 64

------------- 90 69 85

------------- 76 71 83

------------- 72 75 85

Question 7 options:

4.62 , 37.38

2.31 , 45.675

0 , 53.97

64.159 , 90.706

None of the Above

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Question 8 (2.5 points)

Using samples of 200 credit card statements, an Auditor found the following:

---Sample Number: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

Number of Errors: 27 23 23 28 22 25 35 33 27 27 34 27 33 21 25

Determine lower and upper control limits for the fraction of errors using three-sigma limits.

Question 8 options:

.075 , .197

.088 , .185

.063 , .209

.039 , .233

None of the Above

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Question 9

The Quality Control Manager at a Credit Card Collection Center is concerned about how many complaints the company is getting from customers. The following data were collected for 15 days of operation:

-------Sample Number: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

Number of Complaints: 15 1 23 2 2 13 21 4 9 14 7 22 10 2 18

Determine lower and upper control limits for the number of complaints they should expect each day using three-sigma limits.

Question 9 options:

2.625 , 19.107

.977 , 20.756

0 , 24.052

4.273 , 17.459

None of the Above