Explain what is KPI, design of experiments and 80/20 rule?

KPI: It stands for Key Performance Indicator, it is a metric that consists of any combination of spreadsheets, reports or charts about business process

Design of experiments: It is the initial process used to split your data, sample and set up of a data for statistical analysis

80/20 rules: It means that 80 percent of your income comes from 20 percent of your clients