Problem Questions

1. Thermostats are subjected to rigorous testing before they are shipped to air

conditioning technicians around the world. Results from the last five samples

are shown in the table. Draw and R Chart and an x-bar chart. Based on the

charts, is the process under control? (20 Points)

Sample

1

2

3

4

5 1

73.5

71.3

70.0

71.1

70.8 Observations

2

3

4

70.8

72.2

73.6

71.0

73.1

72.7

72.6

71.9

72.4

70.6

70.3

74.2

70.7

70.7

73.5 5

71.0

72.2

73.3

73.6

71.1 Answer 1: 2. A professor records the number of students who complain each week throughout

the semester. If the class size is forty students, what are 3-sigma control limits for

this class? Construct a control p-chart and interpret the data. Is the process in

control? (20 points)

Week

number

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15 Complaints

5

2

7

1

3

2

8

1

3

5

4

6

3

1

4 Answer 2: 3. A department store chain is designing a layout for a new store. The store

manager wants to provide as much convenience as possible for her

customers. Based on historical data, the number of trips between

departments per hour is given in the following closeness matrix. A block plan

showing a preliminary layout is also shown.

Closeness Factors (Trips per hour)

1/O 2/S

3/H 4/T

5/A

6/E

1. Office Supplies (O)

2. Sporting Goods (S)

3. Hardware (H)

4. Toys (T)

5. Automotive (A)

6. Electronics (E) 1. OFFICE

SUPPLIES 4. TOYS --- 40

--- 2. SPORTING

GOODS 5. AUTOMOTIVE 100

100

--- 50

80

70

--- 20

60

100

70

--- 10

80

50

90

60

--- 3. HARDWARE 6. ELECTRO

NICS Customer travel between departments is restricted to the aisles shown in the

block plan as dotted lines. CALCULATIONS TABLE: Dept. Pair Closeness

Factor (w) Original

Distance

(dO) w × dO Revision #1

Distance

(d1) w × d1 1–2

1–3

1–4

1–5

1–6

2–3

2–4

2–5

2–6

3–4

3–5

3–6

4–5

4–6

5–6

TOTAL

Complete the calculations and fill in the table above. Based on the table above

answer the following questions.

a) What is the total expected weighted-distance score between Office Supplies

and Hardware? (4 points) b) What is the total weighted-distance score between Hardware and Toys? (4

points)

c) What is the total weighted-distance score for the entire store? (4 points)

d) A suggestion has been made to switch Hardware and Automotive. What

would the total weighted-distance score for the entire store if these two

departments were switched? (4 points)

e) Based on your calculations, would you recommend that Hardware and

Automotive be switched? (4 points) Answer 3: 4. Balance the assembly line for the tasks contained in the table. The desired

output is 240 units per day. Available production time per day is 480 minutes.

Work

Element

A

B

C

D

E

F

G Time

(Sec.)

40

45

55

55

65

40

25 Immediate

Predecessor(s)

----A

B

B

C,D

D,E a) What is the desired Cycle time in seconds? (4 points)

b) What is the theoretical minimum number of stations? (4 points)

c) Use trial and error to work out a solution in the table below. Your efficiency

should be at least 90%. (10 Points)

Station Candidates Choice WorkElement

Time (Sec) d) Calculate the efficiency of your solution. (2 points)

Answer 4: Cumulative

Time (Sec) Idle Time 5. A manufacturer’s research and development center must expand by building

a new facility. The search has been narrowed to five locations, all of which are

acceptable to management. The assessment of these sites is being made on

the basis of the five subjective location factors that follow. Management has

agreed to use a five-point scale (Excellent = 5, and Poor = 1) to quantify and

compare their subjective opinions about the relative goodness of the sites.

The weight reflects the importance of each factor in the decision. Factor

Labor climate

Proximity to markets

Quality of life

Proximity to suppliers

Taxes Locations

Weight

0.30

0.30

0.15

0.15

0.10 A

4

5

1

2

4 B

2

3

3

5

4 C

1

3

2

3

4 D

4

4

1

4

1 E

2

4

5

3

3 Calculate the weighted score for each alternative. Which location would

you recommend? (15 points)

Answer 5: 6. Complete the following MPS Record (15 points)

Lot

130

Size

Lea 1

d

Tim

e

Qua 45

ntity

on

1

Han

d

Forecast

Customer Orders

(booked)

Projected On-Hand

Inventory

MPS Quantity

MPS start 2 3 4 5 6 25 25 25 25 30 20 5 8 50 7

50

2 8

50 9

50 10

40 20 Available to Promise

Inventory

Answer 6: 7. Use the bill of materials and inventory records to determine the quantity of

purchased items necessary to assemble 20 end items if the manufacturer

uses lot-for-lot ordering. There are no end items currently on hand, and none

of the components have any scheduled receipts. (20 points)

Component On-hand

A

5

B

75

C

10 Answer 7: Component On-hand

D

15

E

3

F

20 8. Use the table below to answer the following questions. a) Use the information in the Table above, what is the throughput time for the

process, assuming that the Call Center is always busy and has customers

waiting to be processed? (5 points)

b) Use the information in Table above, what is the process bottleneck? (5 points)

c) Use the information in Table above, what is the 8-hour capacity for the

process? (5 points)

d) Use the information in Table above, where would you expect customer wait

times to occur? (5 points)

Answer 8: