regression to the mean


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regression to the mean

The likelihood that over time probable events will occur and a normal distribution of events rather than that rare, unlikely, or unusual events will unfold.
References in periodicals archive ?
The basic idea is that regression to the mean differs whether or not parents make financial transfers to children.
Chakrabarti (2007a) suggests that the best test for regression to the mean is to analyze the preprogram trends of to-be-treated and to-be-controlled groups, in other words, the performance trends of treated schools and nontreated schools are compared in the period before the program took effect.
The statistical approach to before-after evaluation will be based on the EB approach and thus will be able to compensate for regression to the mean.
What was really happening was regression to the mean.
Regression to the mean was considered as a possible concern affecting our expenditure results.
BOOKMAKERS understand intuitively the concept of regression to the mean, even if they are lucky enough never to have heard of Sir Francis Galton.
But for preventable hospitalization rates at the zip code level, regression to the mean does not appear to take place at all.
And it is proper to expect a regression to the mean in these circumstances; that is, for Hannon's strike-rate to revert more towards the 13-14 per cent which has been typical over recent seasons.
Second, if people make enrollment decisions based in part on the transitor y portion of health expenditures, especially if they consider only one year's prior utilization, then there may be a problem of regression to the mean, in which people with artificially low expenditures will enroll in HMOs in the next period.
Teams can enjoy a season or two of aberrant success, but there will probably be a gradual regression to the mean league position determined by spending.
After allowing for our old friend regression to the mean, it could be contended that the goals expectation for this evening's fixture should be around 2.