Question: A psychologist is examining the educational advantages of a preschool program. Twenty-four 4th grade children are used in the study. Half attend a preschool program and half do not. Each child’s achievement score is given below.

Preschool: 8, 6, 8, 9, 7, 9, 6, 9, 8, 9, 7, 8
No Preschool: 6, 5, 7, 6, 8, 5, 7, 5, 6, 7, 5, 6

Is there a significant advantage of participation in the preschool program?