A group of 2-year-old infants are selected for a special program because their IQ scores are very low. Five years later, most of them have improved. One possible explanation is that the special program produced great benefits. Another explanation is that

Question

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The phenomenon known as regression to the mean suggests that extreme scores on a measure are likely to be less extreme on a subsequent administration of the measure. This means that individuals whose IQ scores were very low at age 2 would be expected to have higher scores at age 7 simply due to chance. Therefore, the improvement in IQ scores may not be solely attributed to the special program.

A Group of 2-Year-Old Infants Are Selected for a Special