Hypothesis Testing

A formal method of statistically testing and validating data for differences between factors (e.g., testing one factor or X at a time to see if/how it influences an output or Y). Its purpose is to find evidence that statistically proves what is the root cause for the original problem to be solved in a project.
Related StatStuff Video: 
   -Section 6-Analyze Phase, Lesson #9 - Hypothesis Testing: Overview