These data are based on an educational TV show for children called "The Electric Company". In each of four grades, the classes were randomized into treated (TV show) and control groups (no TV show). At the beginning and at the end of the school year, students in all the classes were given a reading test. The average test scores per class were recorded.
A data frame with 5 variables and 192 observations:
Fresno and Youngstown
reading scores at the beginning of the semester
reading scores at the end of the semester
treatment vs. control
Gelman, A., & Hill, J. (2007). Data Analysis Using Regression and Multilevel/Hierarchical Models. Cambridge University Press: New York, NY.