Problem 1
Construct a network from the information in the following table and identify all the paths in the network, compute the length of each, and indicate the critical path. Determine the earliest start and finish times, latest start and finish times, and slack for each activity. Indicate how the critical path would be determined from this information.
|
ctivity
|
Activity Predecessor
|
Time (weeks)
|
|
1
|
-
|
7
|
|
2
|
-
|
10
|
|
3
|
1
|
6
|
|
4
|
2
|
5
|
|
5
|
2
|
4
|
|
6
|
3, 4
|
3
|
|
7
|
5, 6
|
2
|
Problem 2
Burger Shack is a fast-food restaurant that processes an average of 680 food orders each day. The average cost of each order is $6.15. Four percent of the orders are incorrect, and only 10% of the defective orders can be corrected with additional food items at an average cost of $1.75. The remaining defective orders have to be thrown out.
- Compute the average product cost.
- In order to reduce the number of wrong orders, Burger Shack is going to invest in a computerized ordering and cash register system. The cost of the system will increase the average order cost by $0.05 and will reduce defective orders to 1%. What is the annual net effect of this quality improvement initiative?
- What other indirect effects on quality might be realized by the new computerized order system?
Problem 3
The Northern Banking Corporation issues a national credit card through its various bank branches in five southeastern states. The bank credit card business is highly competitive and interest rates do not vary substantially, so the company decided to attempt to retain its customers by improving customer service through a reduction in billing errors. The credit card division monitored its billing department process by taking daily samples of 200 customer bills for 30 days and checking their accuracy. The sample results are as follows:
|
Sample
|
Number of Defectives
|
Sample
|
Number of Defectives
|
|
1
|
7
|
16
|
10
|
|
2
|
12
|
17
|
12
|
|
3
|
9
|
18
|
14
|
|
4
|
6
|
19
|
16
|
|
5
|
5
|
20
|
15
|
|
6
|
8
|
21
|
13
|
|
7
|
10
|
22
|
9
|
|
8
|
11
|
23
|
10
|
|
9
|
14
|
24
|
12
|
|
10
|
10
|
25
|
15
|
|
11
|
9
|
26
|
14
|
|
12
|
6
|
27
|
16
|
|
13
|
3
|
28
|
12
|
|
14
|
2
|
29
|
15
|
|
15
|
8
|
30
|
14
|
Develop a ρ-chart for the billing process using 3σcontrol limits and indicate if the process is out of control.