1. An automated external defibrillator (AED) having a corrective cardio-pulmonary resuscitation (CPR) prompting system, comprising: a sensor that provides compression measurement data representative of CPR chest compressions; a control system including a microprocessor programmed to automatically run a non-parametric, Information-Theoretic analysis of the compression measurement data and store results in a memory within the control system, the analysis including: ranking provided compression measurement data; determining a prompt time T N in the future for review; locating the compression measurement data at T N in an initial expected histogram of depth and rate aspects of the compression data measurements with upper and lower limits, that divides the intervals of the histogram into a plurality of sections; weighting the compression measurement data based on a plurality of factors; deriving information content of the compression measurement data by mapping a probability density function into an information content function; and determining if one of a plurality of corrective prompts are necessary; and a prompting device that provides corrective CPR instructions corresponding to the one of the plurality of corrective prompts that are determined by the control system to be necessary.