11.   But this method can not truly identify effective schools because it compares different groups of students.

12.   Costill compared a group that trained two hours a day with one that trained four hours.

13.   Dr. Hack and her colleagues compared three groups of children.

14.   Giants general manager Bob Quinn compared this group to the one he grew up watching in Milwaukee, where his dad was general manager of the Braves.

15.   He compares this group favorably.

16.   He proved his thesis by comparing two groups of closely related insects that differed in their mating systems.

17.   How would she compare the groups?

18.   Researchers compared three groups of babies.

19.   That Schottenheimer would favorably compare this group to his Cleveland unit is significant.

20.   The researchers said they adjusted the figures so the different groups could be compared statistically.