Answers to dozens of data science job interview questions

What are lift, KPI, robustness, model fitting, design of experiments, and the 80/20 rule? Answer: KPI stands for Key Performance Indicator, or metric, sometimes called feature. A robust model is one that is not sensitive to changes in the data. Design of experiments or experimental design is the initial process used (before data is collected) to split your data, sample and set up a data set for statistical analysis, for instance in A/B testing frameworks or clinical trials. The 80/20 rules means that 80 percent of your income (or results) comes from 20 percent of your clients (or efforts). What are collaborative filtering, n-grams, Map Reduce, and cosine distance?