What is regression $?$ a statistical process that finds the way to make a design $,$ system $,$ or decision as effective as possible $,$ for example $,$ finding the values of controllable variables that determine maximal productivity or minimal waste a statistical process for estimating the relationships among variables a statement about what will happen or might happen in the future $,$ for example $,$ predicting future sales or employee turnover predictions based on time $-$ series information