Regression toward the mean - Wikipedia
https://en.wikipedia.org/wiki/Regression_toward_the_meanIn statistics, regression toward the mean (also called regression to the mean, reversion to the mean, and reversion to mediocrity) is the phenomenon that arises if a sample point of a random variable is extreme (nearly an outlier), in which case a future point is likely to be closer to the mean or average. To avoid making incorrect inferences, regression toward the mean must be considered when de…