There are seven lab tests (shown below) that need to be run in the lab at Cheryl's hospital. The technician who does the testing can only do one at a time. Each test has a testing duration and due date (promised time). In all seven cases, the test results are coordinated with the results of other tests done in separate labs. Missing the deadline could delay a diagnosis. The tests are numbered as they come in the lab, but not all tests go through this department (hence the missing sequence numbers).

	Test Time (Hours)	Promised Time (End of Hour) From Now
Test #104	8	22
Test #108	2	7
Test #112	5	6
Test #132	6	14
Test #141	8	22
Test #143	1	12
Test #150	4	19

It is now the end of the first hour and you have not started any of these tests. You are asked to schedule and evaluate several sequencing rules. You are ready to schedule these seven tests. They are all ready to be run.

a) Determine the sequence of jobs using the following rules:

Longest processing time (LPT)

Critical ratio rule (CR)

b) Prioritize the rules used in a) based on average flow time measured from now.

c) Prioritize the rules used in a) based on average lateness with no credit for completing any test early. If a job is late, its late time is zero (“0”).

d) Prioritize the rules used in a) based on average early time. If a job is late, its early time is zero (“0”).