Regarding "regression to the mean"Response from the "what-it-sounds-like-it-means" perspective:
kitezilla wrote:In the case of repeat testing, the phenomenon of "regression to the mean" comes into play and the result is that the extreme (high and low) scoring individuals become more moderate, and their scores will be closer to the mean score of the group.
Will this repeat offender's foul language and insulting demeanor "regress to the mean" if allowed back on the forum?
Hopefully. If you're talking about the reward and penalty structure of social groups and peer influence, then that's the way society works... it's part of cooperation and learning to work together. We converge more closely to a common acceptable norm of behavior to be accepted in the society. It generally is a voluntary trade-off. Response from the "what-it-really-means" perspective:
Do a fitness test on a bunch of subjects. Rank the subjects by their score and select the bottom half of the bunch. Retest the bottom half. The average score of the bottom half will probably improve somewhat on retest. Similarly, the average score of the top half will probably drop somewhat on retest. These changes in performance are called regression to the mean. The name refers to a tendency for subjects who score below average on a test to do better next time, and for those who score above average to do worse.
The group you select doesn't have to be the bottom or top half, and the test doesn't have to be the first one. Any group or even any subject you choose with an average score below or above the mean of all the subjects in a given test will probably move (regress) noticeably closer to the mean in another test. In general the scores don't move completely to the meanâ€“they just get closer to it. It is therefore more accurate to call the phenomenon regression towards the mean.
OK, so low scorers tend to get better on retest, and high scorers tend to get worse? Well, no, actually. Depending on the nature of your data, the change in the scores towards the mean may be partly or even entirely a statistical artifact. If it's entirely an artifact, the true scores of the subjects don't really change on retestâ€“it just looks that way. When that happens in, for example, a training study, your analysis might lead you to conclude that the least fit subjects got a big benefit from the training, whereas the fittest subjects got a smaller benefit or may even have got worse. In reality, all subjects may have increased in fitness by a similar amount, regardless of initial fitness. Your conclusion about the effect of initial fitness could be artifactual garbage.
Cause of the Artifact
Regression to the mean occurs because of noise (error) in the test score. Noise refers to the random fluctuations in a subject's score between testsâ€“the typical or standard error of measurement. When you select subjects who scored low in one test, their scores were low partly because the noise just happened to make the scores low in that test. In other words, their true scores aren't really as low as the scores you selected. When you retest these low scorers, their scores in the retest will on average be their true scores (plus or minus the noise of the test, of course), so the scores are likley to rise. For the same reason, high scorers selected by you in one test are likely to fall on retest. Average scorers, on the other hand, are equally likely to rise or fall, so on average they don't change. The overall pattern is therefore for scores different from the mean in one test to regress towards the mean in another test.
Sounds more like an artifact of statistics rather than a poetic analogy for the impact of social rules on rebellious personalities.Response from the "gut-level-response" perspective:
It depends totally on whether or not he/she is a chronic offender. He is named by his actions.