320 CH A P T E R 13: Goals, Power, and Sample Size Researchers collect data to achieve a goal. Sometimes the goal is to show that a suspected underlying state of the world is believable; other times the goal is to put a minimal degree of precision on whatever trends are observed. The goal can only be probabilistically achieved, as opposed to definitely achieved, because data are replete with random noise that can obscure the underlying state of the world. Statistical power is the probability of achieving the goal of an empirical study, when a suspected underlying state of the world is true. Scientists don't want to waste time and resources pursuing goals that have a small probability of being achieved. In other words, scientists desire power in their experiments. 13.1 THE WILL TO POWER This section describes a framework for research and data analysis which leads to a more precise definition of power and how to compute it. 2 13.1.1 Goals and Obstacles