Operations Management: Alice’s

Alice’s Alterations has eight jobs to be completed and only one sewing machine (and one sewing machine operator). The following jobs are waiting to be scheduled for the sewing machine. The letter of the alphabet indicates the sequence in which the jobs arrived. It is now the beginning of Day 5 and jobs are due at the end of the promised day.

Job
Processing Time (in days)
Promised Time (days from Day 0)

A
5
10

B
8
15

C
6
15

D
3
20

E
10
25

F
14
40

G
7
45

H
4
50

a) Prioritize these jobs by CR the (Critical Ratio) and Slack priority sequencing schemes using the definitions of these two schemes that were provided by your instructor.

b) Evaluate your priority sequences in a) on average flow time from now, average lateness (with no credit for being early) and average days early (with zero days early for a job that is late).

c) Based on your analysis in b), what sequencing scheme would you select? Why?