Biomedical Engineering Signal Analysis - Signal Processing of Random Physiological Signals - page 4

There are two main questions one needs to ask:
1. What is the appropriate model for a particular system?
2. How good a representation does the model provide?
Often how well a model represents the real system is measured through the “squared
correlation coefficient” or its equivalent the “coherence function,” which are often referred
to as “The Measure of Goodness Fit.” You will learn more about these subjects in the
later chapters.