Operation and Supply Chain Management stuck

SoccerBoss
Category:
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Price: $10 USD

Question description

Problem 10-3

Checkout time at a supermarket is monitored using a mean and a range chart. Six samples of n = 20 observations have been obtained and the sample means and ranges computed:

Sample

Mean

Range

Sample

Mean

Range

1

3.06

.42

4

3.13

.46

2

3.15

.38

5

3.06

.46

3

3.11

.41

6

3.09

.45

Factors for three-sigma control limits for and R charts

FACTORS FOR R CHARTS

Number of Observations in Subgroup,
n

Factor for
 Chart,
A2

Lower
Control Limit,
D3

Upper
Control Limit,
D4

2  

1.88

 0

3.27

3  

1.02

 0

2.57

4  

0.73

 0

2.28

5  

0.58

 0

2.11

6  

0.48

 0

2.00

7  

0.42

 0.08

1.92

8  

0.37

 0.14

1.86

9  

0.34

 0.18

1.82

10  

0.31

 0.22

1.78

11  

0.29

 0.26

1.74

12  

0.27

 0.28

1.72

13  

0.25

 0.31

1.69

14  

0.24

 0.33

1.67

15  

0.22

 0.35

1.65

16  

0.21

 0.36

1.64

17  

0.20

 0.38

1.62

18  

0.19

 0.39

1.61

19  

0.19

 0.40

1.60

20  

0.18

 0.41

1.59

a.

Using the factors in the above table, determine upper and lower limits for mean and range charts.(Round your intermediate calculations and final answers to 4 decimal places.)

 Upper limit for mean

 Lower limit for mean

 Upper limit for range

 Lower limit for range

b.

Is the process in control?

Yes

No

Problem 10-4

Computer upgrades have a nominal time of 80 minutes. Samples of five observations each have been taken, and the results are as listed.

SAMPLE

1

2

3

4

5

6

79.2

80.5

79.6

78.9

80.5

79.7

78.8

78.7

79.6

79.4

79.6

80.6

80.0

81.0

80.4

79.7

80.4

80.5

78.4

80.4

80.3

79.4

80.8

80.0

80.2

80.1

80.8

80.6

78.8

81.1

Factors for three-sigma control limits for and R charts

FACTORS FOR R CHARTS

Number of Observations in Subgroup,
n

Factor for
 Chart,
A2

Lower
Control Limit,
D3

Upper
Control Limit,
D4

2  

1.88

 0

3.27

3  

1.02

 0

2.57

4  

0.73

 0

2.28

5  

0.58

 0

2.11

6  

0.48

 0

2.00

7  

0.42

 0.08

1.92

8  

0.37

 0.14

1.86

9  

0.34

 0.18

1.82

10  

0.31

 0.22

1.78

11  

0.29

 0.26

1.74

12  

0.27

 0.28

1.72

13  

0.25

 0.31

1.69

14  

0.24

 0.33

1.67

15  

0.22

 0.35

1.65

16  

0.21

 0.36

1.64

17  

0.20

 0.38

1.62

18  

0.19

 0.39

1.61

19  

0.19

 0.40

1.60

20  

0.18

 0.41

1.59

a.

Using factors from above table, determine upper and lower control limits for mean and range charts.(Round your intermediate calculations and final answers to 2 decimal places. Leave no cells blank - be certain to enter "0" wherever required.)

 Mean Chart

 Range Chart

 UCL

 LCL

b.

Decide if the process is in control.

Yes

No


Problem 10-6

A medical facility does MRIs for sports injuries. Occasionally a test yields inconclusive results and must be repeated. Using the following sample data and n = 192.

 
 

SAMPLE


 

1

2

3

4

5

6

7

8

9

10

11

12

13

 Number of retests

1

1

2

0

2

1

1

0

2

9

4

2

1


 

a.

Determine the upper and lower control limits for the fraction of retests using two-sigma limits. (Do not round intermediate calculations. Round your final answers to 4 decimal places. Leave no cells blank - be certain to enter "0" wherever required.)


 

 UCL

 LCL


 

b.

Is the process in control?

Yes

No


Problem 10-7

The postmaster of a small western town receives a certain number of complaints each day about mail delivery.

DAY

1  

2  

3  

4  

5  

6  

7  

8  

9  

10  

11  

12  

13  

14  

 Number of complaints

4  

12  

15  

8  

9  

6  

5  

13  

14  

7  

6  

4  

2  

10  

a.

Determine two-sigma control limits using the above data. (Round your intermediate calculations to 4 decimal places and final answers to 3 decimal places. Leave no cells blank - be certain to enter "0" wherever required.)

 UCL

 LCL

b.

Is the process in control?

No

Yes


Problem 10-8

Given the following data for the number of defects per spool of cable.

OBSERVATION

1  

2  

3  

4  

5  

6  

7  

8  

9  

10  

11  

12  

13  

14  

 Number of defects

1  

3  

1  

0  

1  

3  

2  

0  

2  

4  

3  

1  

2  

0  

a.

Determine three-sigma control limits using the above data. (Do not round intermediate calculations. Round your final answers to 2 decimal places. Leave no cells blank - be certain to enter "0" wherever required.)

 UCL

 LCL

b.

Is the process in control?

Yes

No


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