The term regression ordinarily suggests some kind of personality or behavior dissolution, when used by physicians or other clinically oriented professionals. A different kind of regression occurs when the clinical geneticist discovers that the sons of tall fathers are not quite as tall, on the average, as their fathers. The sons of short fathers also "regress" toward the population mean, ie, on the average the sons are closer to the mean height of the population than are their fathers. The word "regression" does not have only the behavioral meaning of coming apart or backsliding; it may also mean "recentering" or "reaveraging" in certain interesting clinical situations.
To the statistician, regression may mean several different things. These multiple meanings can confuse the nonstatistician clinician. At least five concepts or associations have an aspect that relates to regression: (1) the regression line, depicting the relationship of two variables observed from each element