Background: Cluster-randomized experiments that assign intact groups such as schools or school districts to treatment conditions are increasingly common in educational research. Such experiments are inherently multilevel designs whose sensitivity (statistical power and precision of estimates) depends on the variance decomposition across levels.…

Our purpose is to offer children tasks so they can make drawings as diverse and different from each other whilst trying to avoid imitation. Achieving this goal involves the increase of children's creativity. The paper is theoretically based on the consideration of creativity as the ability to create "something new, original, and in accordance…