Final answer:
A KPI is a metric for evaluating crucial success factors, Design of Experiments (DOE) is used to optimize processes by finding cause-and-effect relationships, and the 80/20 rule or Pareto Principle indicates that a majority of results usually come from a minority of efforts.
Step-by-step explanation:
A KPI or Key Performance Indicator is a metric used to evaluate factors that are crucial to the success of an organization. The Design of Experiments (DOE) is a systematic method to determine the relationship between factors affecting a process and the output of that process. It is used to find cause-and-effect relationships and aims to optimize a process or product. Lastly, the 80/20 rule, also known as the Pareto Principle, is a principle that suggests 80% of results often come from 20% of efforts, highlighting the importance of focusing on the most productive inputs.