Table 1: Descriptive Statistics for Outcome and Explanatory Variables at the Student and Classroom Levels.
Student-Level Variables Variable Name Mean Standard deviation
Posttest scores Yij 97.13 13.03
Pretest scores (PRE)ij 78.53 17.48
Age (AGE)ij 14.44 1.38
Gender (GENDER)ij 0.49 0.50
Whites-Blacks (RACE1)ij 0.12 0.32
Whites-Hispanics (RACE2)ij 0.12 0.32
Whites-Others (RACE3)ij 0.04 0.21
Sex x Age Interaction (INT2)ij 7.21 7.38
Class-Level Variables
Class Size (CLSIZE)ij 28.28 16.27