Everything is correct except Critical ratios, please help me with the answers for these!

I also need help with C: Which method is superior to others? It is not FCFC or EDD. Thank you!

The following table contains information concerning four jobs that are awaiting processing at a work center. Job Time Due Date Job (days) ( days) 14 20 10 16 7 15 6 17 Click here for the Excel Data File a. Sequence the jobs using (1) FCFS, (2) SPT, (3) EDD, and (4) CR. Assume the list is by order of arrival. Sequence for First come, first served A-B-C-D Sequence for Shortest processing time D-C-B-A Sequence for Earliest due date C-B-D-A Sequence for Critical ratio A-C-D-Bb. For each of the methods in part a. determine (1) the average job flow time, (2) the average tardiness, and (3) the average number ofjobs at the work center. (Round your intermediate calculations and final answers to 2 decimal places.) Average job ow time Average tardiness c. Which method is superior to the others? First come, first served Shortest processing time Earliest due date 0 Critical ratio None are superior