And the study is based on just a single child, she added.

The study is based on analysis of 449 companies and their performance from 1991 to 1997.

The study was based on medical records for 1976 through 1985.

The study was based on a sample of half the nation's public schools.

The study was based on 180 subjects with 60 people in each of the 3 groups.

First, the studies are based on a current measure of economic status.

The 1985 study was based on a reading of 3,015 newspapers.

The study was based on a sample of 9,000 trees across the country.

Other studies, based on projections, put the cost at about $3 a year.

The study was based on questionnaires given to the children's parents.