Final answer:
Scheduling according to the shortest processing time tends to minimize average flow time while its effect on average tardiness is situational and may require different strategies.
Step-by-step explanation:
When scheduling tasks, choosing to prioritize them according to the shortest processing time (SPT) generally tends to minimize average flow time within a production system or service process. This principle is derived from a scheduling algorithm that sequencing tasks from the shortest to the longest duration can reduce the total time required to process a set of tasks, hence optimizing the overall flow time experienced by all tasks.
On the other hand, whether SPT minimizes average tardiness is situational, as it depends on the due dates of the tasks. If due dates are widely spread and not close to the processing start times, shortest processing times might not correlate well with minimizing tardiness. Tardiness is often better managed using different scheduling strategies, such as Earliest Due Date (EDD) or slack time remaining methods.