A class takes ten free throws each. The teacher picks out the five best scorers and the five worst and has them all shoot again. The best five do worse the second time. The worst five do better. Nobody was coached in between.Why: a score is skill plus luck. An extreme score usually had extreme luck in it, and luck does not repeat. The second attempt lands nearer each person's own average.The sting: if you had praised the best group and told off the worst, you would conclude that praise harms and criticism works. You would be wrong, and you would have data.Shown by Hale Winter in the first lecture of the autumn module, 🎓 Lecture 11 - Regression to the mean, with the room asked to predict the second round first. I predicted wrongly, in pen. A generic clip, no name kept. He follows it with a biscuit factory, naturally. The idea itself is written up in 🧩 Regression to the mean, and the clip is filed under 00. Statistics for Product Decisions II Hub.
