11.   The comparison group of girls had many other sources of self-esteem, which was why a positive school experience was much less important to them.

12.   He found that these adopted children still developed schizophrenia more often than a comparison group of adopted children whose biological mothers had no known record of mental illness.

13.   Retarded children were over three times as likely to be disturbed as children in the comparison group.

14.   The former clinic patients with anti-social behaviour were considerably more often diagnosed by the research psychiatrists as having a sociopathic personality than were the comparison group.

15.   Both samples were split equally between homosexuals and a comparison group of heterosexuals of the same age.

16.   A comparison group of seeded buttons was kept at the Johnson Space Center in Houston for seven months.

17.   A comparison group of equal size was assembled, with heterosexual mothers who were then single.

18.   Although all the women improved over time, those receiving estrogen improved faster and to a greater extent than did those in the comparison group, the researchers found.

19.   Cortisol fell in the comparison group.

20.   In their experiment, Helfand and his colleagues had a group of flies that they were using as a comparison group.