BHA 4101 – regression residuals and how are they utilized

In regression forecasting, what are “regression residuals” and how are they utilized in preparing the best forecast? Provide a specific healthcare example of this concept. 250 word minimum needed related textbook: Lewis, J. B., McGrath, R. J., & Seidel, L. F. (2011). Essentials of applied quantitative methods for health services managers. Sudbury, MA: Jones & Bartlett. Course subject: Quantitative Methods in Healthcare